Enemy Scan

"Are you, are you scanning me in freefall now? How do you even do that?! What are you, readin'?!"

- Ridley, Slowbeef's Let's Play of Metroid Prime 3

An item, ability, or spell that when used provides the player with otherwise hidden information about the current enemy. This will often reveal the enemy's Hit Points, Mana Meter, attacks, weaknesses (in RPGs, especially magic-based ones), or may just provide a general description of the enemy. Often shown in the form of Stat O Vision, even if it's a magical spell.

Some games feature a Monster Encyclopedia of sorts that may be filled if the player wants Hundred Percent Completion (in turn requiring the player to traverse the world and perform this on every single enemy). Frustratingly, this can result in a Lost Forever if the enemy (or a specific variation of it) only appears a limited number of times.

This may or may not work on bosses, especially the Final Boss. But it usually does work on Helpful Mooks.

Can become a Useless Useful Spell if it can only scan weak enemies you don't need to know much about to defeat.

Anime and Manga

 * The Pokédex in the Pokémon anime.
 * Chopper in One Piece is capable of doing this in his intelligence oriented form, Brain Point, while under the effects of a Rumble Ball.
 * The various incarnations of the Digimon franchise have the Digimon Analyzer, always presented in a different form. In Adventure and 02 it was ostensibly a program on Koushiro's laptop, Tamers and Frontier relegated the roles to the kids' Digivices, and the Savers incarnation seems to have given the role to Miki and Megumi's computers at DATS HQ or Touma's laptop.
 * Dragonball Z features "Scouters", special devices worn over the eyes which can measure the Power Levels of enemies.
 * And a nasty habit of exploding.
 * Guy from Gao Gai Gar apparently has one of these in the form of a scouter-looking lens. He only uses it once, however, making it seem extremely random when he shouts "Library!" in the middle of a tense scene.
 * One of Nijima's 'evil alien/demon/whatever' powers in Kenichi the Mightiest Disciple is the ability to look at fighters in a strange way and then size up their strength.
 * In Needless, Disk's Scan ability can retrieve information about any person she meets, most notably on their Fragment ability.
 * But more importantly bust, waist, and hip measurements.
 * The R.E.A.D. software installed into the cellphones of the Air Gear universe allows people to check the statistics of nearby A-T riders. These include their power level, class and the number of tricks they have performed.

Live Action TV

 * Airwolf features a similar system, which shows a line drawing of the attacking aircraft (or ship) with basic info on its weapons. As it finds the info, images of other aircraft are seen in a "searching display", including the Tu-95 "Bear" and the Tu-22M "Backfire".

Tabletop Games

 * Dungeons and Dragons 4th edition even has an item called the "Goggles of Aura Sight" which tells you how many HP the monster has, and any diseases or disease causing effects on him.
 * In at least some of the editions there are the knowledge skills, some of which will tell you information about a creature you encounter upon a successful roll. How much info depends on the roll.

Video Games

 * The Scan/Libra ability in Final Fantasy tends to reveal an enemy's current health and elemental weaknesses, among others. Depending on the incarnation, you may have access to this information for the rest of the battle.
 * A boss from Final Fantasy VIII and Final Fantasy IX actually used Scan on your party, which made little sense since the boss' attack patterns never changed after that. Plus, you can scan your own party. Scan can also be equipped to your characters in VIII for a stat increase, but the gain is maybe a 1% boost, so one would pretty much only do this if they were bored.
 * Final Fantasy IV features a mini-boss that will scan a party member and then unleash an instant kill attack on whoever was scanned. Also, one enemy in the final dungeon scans itself, but uses this to trick the player, who receives a nasty counterattack if they use the enemy's weakness (lightning).
 * Also after casting Libra/using a picture book on an enemy, from that point all enemies of the same type have their current HP displayed.
 * Final Fantasy III (The Japanese one that got a DS remake) features Hyne, a boss that changes his weakness frequently throughout the battle. Theoretically, this fight should be made considerably easier through either constant use of the Libra spell (of which you only have a few shots at that point in the game) or use of, as the game suggests several times, the Scholar class, for which this is a free action. In practice however, instead of wasting a turn scanning and then having Hyne change his barrier again before you act next turn, it tends to be easier to just throw spells of different elements at him so you're sure one of them hits his weakness.
 * Or just use a Geomancer.
 * Final Fantasy X 2 even allowed you to learn upgraded versions of the ability: at level 2, you could rotate the resulting image of the enemy to look at it from different angles, while at level 3, you could target your own party members with the spell. Hm, I wonder what the point of that feature was?
 * Final Fantasy X had two versions of this: 1) The Sensor ability let you see the condition (HP, MP, weaknesses, ect.) of the highlighted enemy in question. And 2) The Scan spell that let you see with in-depth detail what the target has (Ronso Rages, immunities, a tip about the enemy, etc.). The fact that a lot of the strong enemies are immune to sensors pretty much makes the usefulness of scanning drop to zero once you get to the final dungeon.
 * Libra is a tech point consuming ability in Final Fantasy XIII, and it is vital to being able to kill mooks properly. As in, your characters will accidentally heal and debuff the enemy if they don't get a little intel first. Once an enemy is scanned, your allies' AI will automatically exploit any weaknesses the foe in question has (Ravagers attacking with the appropriate elemental attacks, and Saboteurs casting whatever status debuff(s) the enemy is susceptible to).
 * A Librascope is a one use item (that doesn't consume TP) that's equivalent to casting Libra on every enemy in the battle, twice (which is how many uses of Libra it takes to build a complete profile on a enemy). For most mooks, you can skip the scans (good advice given that Librascopes are rare/expensive (and gil is rarely found unless you farm items, anyway) and TP requires fighting to earn) and just fight them: Any immune or absorbed elements are instantly noted after they're used, and you can get a full profile after killing four or five of the mook in question.
 * Libra is also vital in Final Fantasy XII. It is a technique so it costs no MP to use and it lasts quite a while. Libra will show a targeted enemy's HP, reveals any weaknesses they have, and also reveals any traps in the field. Some accessories grant Libra status automatically.
 * Final Fantasy Tactics a 2 doesn't have abilities that let you read enemy HP since you can see their HP at all times, but it did have abilities that let you scan enemies for what kinds of loot they were carrying.
 * Jeff's Spy ability in Earthbound provided a readout of the target's offensive and defensive stats.
 * Its predecessor MOTHER had Check, which worked the same, but could be used by anyone and also provided a comment about the enemy.
 * Likewise, Boney in Mother 3 can Sniff an enemy to deduce their type and vulnerabilities. Some enemies have no scent, and some are too pungent for Boney to handle sniffing them.
 * Spectacles/Magic Lenses in the Star Ocean series.
 * Deus Ex has a scanning augmentation. It was more useful than the typical scan since it increased your weapon accuracy, making it a very viable choice for most combat situations.
 * The Tattle ability in the Paper Mario games. Notably, once you'd tattled an enemy once, you'd be able to see that enemy type's current HP forever. There's also a badge that enables the player to see HP without tattling, as long as it was equipped. The first game didn't allow you to view the tattled enemies in the menu. The second game did, and any tattles that would otherwise be Lost Forever ended up in Frankly's trashcan for you to pick up. Humorously, the enemies that mimic your partners can and will Tattle on you if mimicking the right character.
 * In Super Paper Mario, the tattle log from the previous games is replaced by cards that also increase the attack power against these enemies in addition to listing their stats for reference. There are also cards for bosses and other characters that have no additional effect.
 * Mallow's Psychopath ability in Super Mario RPG. When the action command succeeds, it also reveals the thoughts of the enemy, which are usually just flavor but sometimes reveal a weakness or attack strategy.
 * Navi in The Legend of Zelda Ocarina of Time, her snarkier Suspiciously Similar Substitute, Tatl, in The Legend of Zelda Majoras Mask, and Fi in The Legend of Zelda Skyward Sword, are three characters capable of doing this. There's also the figurine gallery and mask in The Legend of Zelda the Wind Waker, which would actually display a Life Meter for enemies.
 * The Analyze spell in Secret of Mana. It could even be used on randomly-dropped treasure chests to test for traps.
 * Star Wars: Jedi Academy had Force Sense, which in single-player mode showed not only enemy health, but also highlighted enemies, equipment, invisible symbols, and other useful tidbits, even through walls.
 * The Scan Visor in the Metroid Prime games (although it can also be used on objects). You were actively encouraged to scan literally everything you came across, especially since scans count toward Hundred Percent Completion and some scans (especially bosses) could be Lost Forever. The Scan Visor apparently knows everything in the universe, since a quick two-second scan of literally anything will give you a name, classification, 3D models of its body, strategies for battle, its origins, and anything else you can think of.
 * In Metroid Prime 3, this is a very important method of acquiring tokens to unlock additional goodies, each new enemy scan and lore scans (of certain objects that record the history of the various places within the game) awards a red or blue credit respectively
 * This is played with in the last level of the series:
 * Angband has the "Probing" ability, which gives the current hit-point total of monsters; in some variants it also gives information about resistances, vulnerabilities, and attacks.
 * Kingdom Hearts has a version of this that's more useful than normal, mostly because it's on/off rather than take a turn to use it once.
 * Much more useful than you think at first. Unlike most Enemy Scan spells, it does not matter how powerful, how large, or how ugly the boss is, the spell ALWAYS works.
 * Chrono Trigger had the "Sight Scope" item (equipped to Lucca at the start of the game), which allowed the wearer to see all enemies' HP.
 * Chrono Cross has the green elemental spell Infoscope, with the same effect.
 * In Sly Cooper and the Thievius Raccoonus, the Binoc-u-com can be upgraded to provide an Enemy Scan. The scan is of little practical use; it only gives humorous enemy descriptions.
 * As in the anime (see above), the Pokédex in the Pokémon games acts as this, with varied usefulness. A prominent use for it is to see where one could catch some of the rarer Pokémon.
 * In terms of actual battle mechanics, Pokémon with the ability Frisk will reveal the opponent's held item, and the abilities Anticipation and Forewarn can give clues on the opponent's moves.
 * X-COM: Enemy Unknown had a device that allowed one to read the stats of detected aliens, particularly useful for tracking down an enemy officer to know who to stun for interrogation and who you could just blow away
 * The Fallout games had the Awareness perk, a useful trick that allowed you to know how many hit points a person had left, their status (crippled limbs, blinded, etc.), and what weapons they were carrying.
 * Once you obtain the camera in Bio Shock, taking photos of enemies would uncover weaknesses and grant you more damage against them when using certain weapons.
 * The stethoscope in Nethack allows you to determine the Hit Points, alignment and speed of an adjacent monster.
 * Wand of Probing does the same, also telling the monster's inventory, if it has any.
 * Magicbane has a probing ability, too.
 * And you can target the stethoscope at yourself, which is one of the easiest ways to find out your own alignment (you need it to be above a certain value before more plot happens).
 * The Analyze Monster spell in Might and Magic does precisely that. As I recall, Bards Tale and Wizardry had similar spells.
 * Might and Magic VI had a the Horn of Ros, a very difficult to find item that showed the exact number of hit points enemies have instead of the usual health bar. Later games had the Identify Monster skill, which at high skill levels would show all the enemy's stats, including resistances (useful since many enemies are resistant to specific schools of magic).
 * In Tales of Symphonia, monsters would appear in the Monster Encyclopedia after you've defeated them; however, no detail would be listed unless you scanned them with Magic Lenses - and even then certain details would be left out if you hadn't used the right character. You gained a title from collecting all detailed scans of enemies, an action that required more than one playthrough. Mercifully, you didn't need to get the full scans, and Magic Lenses cost a measly 10 Gald.
 * The magic lenses were also in other games in the Tales Series, such as Tales of Vesperia and Tales of Phantasia, but Tales of Symphonia: Dawn of the New World got rid of the magic lenses and just gives you free access to the information.
 * In Tales of Destiny, Philia could just use her own "magic lenses" to scan enemies rather than waste items.
 * The Scan spirit command in Super Robot Wars lets you see an enemy unit's statistics and only costs 1 SP to use, but since you can see the exact same information after you've traded blows with the enemy once, it's generally not worth it.
 * Later games make it more useful by also decreasing the enemy accuracy by 10% for one turn.
 * Enemy scanning is an important part of Shin Megami Tensei games. Once you have encountered an enemy, you get its basic data, like name, type and usually HP and MP. By attacking it with different attacks, you get to know (and keep info on) its strengths and weaknesses. This info is kept if you ever meet any more of it (and usually applies to any of its Palette Swaps), which is handy. If you ever fuse some of the demons yourself, you also get all the info you need on its wild cousins, should you ever encounter them.
 * Devil Survivor averts this by giving you all the info you need straight off the bat.
 * Fuuka: Give me a sec, I'll scan the target.
 * As the only medical doctor of the 3 doctorates in Eternal Darkness, Max Roivas can autopsy the corpses of his foes if he gets to them before they dissolve. This is mostly for the fun of listening to his ramblings later on, though; you can usually figure out the enemy weaknesses yourself.
 * Hunters in World of Warcraft have the Beast Lore spell, which reveals diet, stats, health, mana, etc. As the name implies, it only works on enemies classified as beasts (most animals).
 * Also works on druids that are shapeshifted into animal form. They are not tameable.
 * The power Surveillance from City of Villains and City of Heroes, which not only lowers the defense and resistance of a single target, but allows you to see the scanned enemy's "real numbers".
 * Xenosaga games have the "Analyze" Ether.
 * Wild Arms games all have some way of analyzing enemy stats. In Wild ARMs: Alter Code F, you can complete a monster encyclopedia by scanning enemies; getting at least 50% will get you an Ex File Key.
 * Blue Dragon has a magic book which lets you do this. Surprisingly, it's often the best (or only) way to find out the boss's weakness.
 * Mana Khemia Alchemists of Al Revis has the main character's "Analyze" skill. Use it once on an enemy, and it will show that enemy's statistics, as well as any subsequent enemies of the same type (not counting Underground Monkey/Palette Swaps).
 * Tohsaka gives Shirou an unnamed book in Fate Stay Night that scans the abilities of a Servant and puts it into a form that the reader will easily understand if they look at it. Shirou's mind apparently puts things into RPG stat formulas with letter ranked abilities and bizarre numerical descriptors for Noble Phantasms.
 * The PKE Meter and Ecto Goggles in the modern Ghostbusters video games have this feature. The more thoroughly you scan a ghost, cursed artifact, spectral emanation, or any other from an assortment of supernatural entities, the more gameplay hints and quirky trivia you will discover in the Tobin's Spirit Guide.
 * Kingdom of Loathing has the Dwarvish War outfit, with a hat (displays attack in runes corresponding to numbers in base 7), kilt (has blinking lights that correspond to defense in base 7), and mattock (displays HP by displaying brightness, one level for each 7 HP they have left). They also have the Detective skull offhand item which gives a good estimate of HP.
 * The VGA remake of Quest for Glory 2 adds a completely new side-quest which rewards you with a logbook. This logbook records combat information about the various monsters you meet in the game.
 * Parasite Eve had Scan, which obviously showed HP and weaknesses, plus any other special characteristic like easily confused or can be easily robbed. The sequel had certain armors that let you read the HP of your targeted foe, but naturally would not display a boss' HP.
 * While regular enemies had no HP bars to scan, bosses in Star Fox 64 would automatically have the HP displayed as long as Slippy was present. Well, except for the Star Wolf team, the Bolse reactor core, the Copperhead missiles, and the Saucerer, considering that the core still eventually appears even if you never shoot the hatches and one bomb is enough to obliterate the core. Come to think of it, with the usual handling of boss battles that consist of multiple enemies, it's a wonder that the gauge appeared for the Shogun Warriors that make up the first half of the Sector Y boss battle.
 * Raptor : Call Of The Shadows had a powerup which reveals the remaining health of bosses.
 * In Lords Of Magic, each faith has a spell to detect the opposite faith's units. (This is also a kind of Aura Vision)
 * In Dubloon, Ricky begins with "Identify" move which lets him see enemies stats and weaknesses. Later, there's a spyglass item which, when used in battle, reveals all enemy weaknesses at once.
 * Maple Story, with its love of Level Grinding, allows you to "scan" monsters by killing them and having them randomly drop a card that, when picked up, will place some information into the Monster Book. Of course, the game doesn't give you all the info at once. You have to pick up five of the cards to get all the info about them, but some of the info is very useful, like where the monsters spawn and what they drop.
 * In Endless Ocean, you do this with your hands by groping interacting with the various sea life (and other animals on the deck of your boat). Your reward for doing this, and the major point of the game, is an encyclopedia filled with interesting facts about the various species you've found.
 * Team Fortress 2's Spy can see the names and health bars of any enemy he aims at, allowing him to give valuable info to his teammates, pick off wounded targets, and avoid falling victim to Because I'm Jonesy. Medics using the Solemn Vow also have this ability, and the Beta also gives this ability to Medics who use the Vita-Saw, in order to make it more powerful.
 * Resonance of Fate has an item named "Clairvoyance" that you throw at an enemy and it allows you to see its details...somehow.
 * Distorted Travesty is a platformer that makes enemy scans an essential part of the gameplay as, among other things, the scan tells you what attacks, or sequence of attacks, will cripple an enemy. The sequel takes this even further by altogether removing your physical attack, leaving you with nothing but magic to defend yourself with, so knowing which elements the enemy is resistant or weak to becomes absolutely essential.
 * The magic ring in The Adventures of Robin Hood lets you scan everyone giving details of their health, wealth, alignment and other stats
 * Ancient Domains of Mystery has stethoscopes, which can be used on enemies to measure various stats. Doesn't work on undead and constructs, because they're not alive.

Western Animation

 * Fishlegs develops (or already has) this skill in How to Train Your Dragon, being instantly able to identify a dragon's major abilities and weaknesses in a single glance (and doing so in hilariously familiar Tabletop Gaming terms).
 * He's actually the resident dragon geek; he's not coming up with this stuff with but the merest glance, he's reciting from memory something he taught himself by rote years ago. Notice that he's less definite regarding the Red Death; they've never even heard of this thing before, so the best he can do is hazard an educated guess based on what the Vikings collectively know about the dragons they have encountered.

Real Life

 * Technology is under development that will use radar to recognize specific types of weapons concealed on a person.
 * Google's Project Glass is attempting to create this for real life by linking live recorded images to information about them on the internet.