Segmented Serpent

The Segmented Serpent is an enemy which is made up of lots of mostly identical pieces that usually all move along a single path like a train on tracks, though rare specimens may have more realistic snakelike undulating movement. It normally has weapons mounted at least in the head and/or tail piece, and can also use its body to block the player, forcing them to take evasive action.

This enemy type is almost ubiquitous in Shoot'Em Ups, but also appears in other games. Because it normally appears in 2-dimensional games, it can often move through its own body and form closed loops to trap the player. Burrowing into the surrounding terrain and reemerging is another common tactic.

Often only shots to the head will kill a serpent. Death is typically a segment-by-segment explosion from the point of destruction. Alternatively, destroying the head will turn the next segment into a new head and it must be destroyed one piece at a time.

If all segments are vulnerable from the start, it may turn into an Asteroids Monster when destroying a middle segment causes it to split into two smaller creatures.

Segmented serpents are quite easy to design; they're simply a line of enemies, each told to follow the one in front. Some games seem to be aware of how lazy this looks, and put additional work into making them look good: the second boss in the Taito game Metal Black is an excellent example, with segments which properly change shape depending on their position and angle.

Anime and Manga

 * Mobile Suit Victory Gundam has the modular mobile armor Doggorla, whose segments can function as Attack Drones.
 * At least two of these show up in Gatchaman.

Tabletop Games

 * Mortasheen takes this to silly lengths with the Bratwurm, which is one of these made entirely out of hot dogs!

Action Adventure

 * Moldorms in The Legend of Zelda series, which have to be defeated by hitting their tails. Possibly also Twinmold from The Legend of Zelda: Majora's Mask. Also, Volvagia from The Legend of Zelda: Ocarina of Time.
 * Although Volvagia's movement looks like a Segmented Serpent, it is a single 3D object rather than a chain of segments.
 * An example of an actual segmented serpent from Ocarina would be the serpents that appear in Jabu-Jabu's belly.
 * Also Gohma from The Legend of Zelda: Link's Awakening. Plus, the Slime Eel from the same game. Also moldorm, the first boss, and the miniboss Lanmola. Obviously this game was very big on segmented serpents.
 * The Gohmas in Link's Awakening are actually 2 different monsters, rather than segments. They are rather far apart from each other as well.
 * Also Skeldrich from The Legend of Zelda: Spirit Tracks.
 * The second form of the boss of Turtle Rock in A Link to The Past is an unusual example, since its weak point is in the middle.
 * Barba from Zelda II was one of the first examples.
 * La-Mulana has Amphisbaena, Bashumu (a Mini Boss in the Dimensional Corridor) and Nu Wa.
 * DeepDive dragon boss from An Untitled Story. Strange in that he is a Stationary Boss, and his weak point is one specific segment of his neck.
 * The Basilisk in the Harry Potter and the Chamber of Secrets game is this.
 * The boss Centipede in Deadly Towers.

Action Game

 * Gunstar Heroes features Valvalis in the Dice Palace, as well as the Core Guard System's "Unit of the Dragon".
 * An early boss in Strider is a long, segmented Transforming Mecha that slithers around in the air and is made of politicians.
 * Orchidee, the third proper boss of P.N.03, is a mecha-centipede on rails.

Beat'Em Up

 * Battletoads for the NES had these. But instead of killing them, you had to climb them as they slithered around spiked balls hovering in the air.
 * The Battletoads arcade game's second boss was abit of a subversion in that one of these snakes was a boss. It still looks segmented, but all he does is bite at you from the background.
 * Muramasa: The Demon Blade features a couple of centipedes as Kisuke's second boss that crawl over the buildings and fire flames out of the various segments.

Platform Game

 * Fracktail and Wracktail in Super Paper Mario.
 * Fire Snakes in Super Mario Bros. 3.
 * Wigglers from the Super Mario Bros. series. Technically, they're actually more like caterpillars, but the way to defeat them focuses on killing each segment at once.
 * Super Mario 3D Land featured floating snakelike enemies made almost entirely out of brick and "?" blocks.
 * Super Metroid features Botwoon, the water serpent. Metroid Fusion features Serris, a snake with super speed. Metroid Zero Mission features the Charge Worm and Acid Worm. They all must be shot in the face.
 * Dynamite Headdy has a skippable robot dragon Mini Boss on the upper path toward the end of Scene 2-2, which can be fought for a Secret Bonus Point.
 * Megapede, the final arena boss in Ratchet and Clank Up Your Arsenal, where blasted-off segments turn into irritating cannons that distract you from the main boss.
 * Alien Soldier has about four enemies of this variety. Oddly, one of them attacks by breaking apart and hurling all its segments at you.
 * Turns up from time to time in the Sonic the Hedgehog series. The Caterkillers from the first game come to mind, as do the Caterkiller Jr.'s in Sonic 3, and from Sonic and Knuckles, the jumping worms in Sandopolis and the flying worms in Lava Reef. Also, the first phase of one of the bosses in "Sonic2" involved this, plus one of the bosses in Sonic Advance 2. Sonic Advance 3 also involved these as a regular enemy.
 * Eggman builds one as the final boss battle in Sonic's storyline in Sonic Adventure.
 * Crystal Caves has a rare enemy which looks like a green snake built of four segments. Shooting it in the head causes it to become shorter.
 * Mega Man 7 has these in Junk Man's stage.
 * Mega Man X has two on Launch Octopus' stage: One that actually obstructs the path leading to the boss, and must kill to advance, and another that blocks the way to a secret Heart Container. Neither can be harmed in any way except by shooting the head or the tail, and those are the only parts that can hurt you, so you can go for a ride on its body and pelt the head or tail with shots as much as you want.
 * In Mega Man Zero 2, a variation is used in an early boss fight, where it's the battlefield that's the segmented serpent. The boss is simply a snake-themed robot master.
 * One of the bosses fought in world 8 in Monster Party.
 * Bug!! has a borderline example in the form of... "caterpillars". They will fire out their "segments" one by one, and only after all the segments have been fired out will the "head" (actually an insect by itself) run away and become vulnerable.
 * Terraria has several of them, but the most prominent would probably be the Bone Serpent in the Underworld, and the Eater of Worlds in the Corruption (the latter adding a bit of Asteroids Monsterto the fray, with each broken off part coming back to haunt you in great numbers if you're not careful).
 * Ghosts N Goblins has multiple battles against dragons of this type.
 * A curious example is the giant earthworm that appears in Hammerin' Harry. It extends its front part to squirt blue stuff at you and generally looks very out of place in the game.
 * Stinkoman 20 X 6 has Saargtsson, a giant snake that jumps out of lava and shoots lasers at Stinkoman.
 * Green Grub from Kid Niki: Radical Ninja.

Rail Shooter

 * The dragons in Space Harrier are quite impressive-looking examples of this for a 1985 game. Averted in the PlayStation 2 remake, where the dragons have more complex 3D models.
 * Night Striker has the Dragon Head bosses, which are robotic sea worms. Unlike most examples, their whole body is vulnerable. Which is a good thing, because you'll have to fight more than one in later levels.

Real Time Strategy

 * Command & Conquer 3: Kane's Wrath has the Mechapede for the Scrin faction. It's customisable and quite useful since all of its pieces are armed.

Roguelike

 * Nethack includes the long worm, which will likely split in half if you attack the middle.

Role-Playing Game

 * One of the toughest viruses in the first Mega Man Battle Network is a three-segmented serpent. It couldn't trap you, but it could easily block attacks to its head with its two body segments. Luckily, you only ever have to deal with just the snake, being one of two virus types that are only ever fought by themselves.
 * Mega Man ZX, on the other hand has Giga Aspis, which as an intro level boss is one of the easiest enemies you'll face.
 * The Pot Centipede from Kingdom Hearts. Actually, the monster itself was nothing but the head and tail piece; the rest of it was made of of Pot Spiders. While you could destroy the Spiders to make the Centipede smaller, the only way to deal damage to the boss itself is to attack the head or tail.
 * Secret of Mana has two snake bosses like this.
 * Pokémon Ranger subverts this with Steelix. It's made up of several chained segments, unlike all the other Pokemon in the game, but due to the way the game plays you don't target the segments at all. Instead, you have to draw circles around the whole beast in a continuous loop while it slithers around, with the segmentation simply making it bigger and more flexible. Known for being very, very, hard.
 * Zigzagged in Final Fantasy XIII, of all games. The fal'Cie Dahaka is a flying serpent creature that resembles a chain of beads, and while the "bead" segments do have to be destroyed, . But in true Segmented Serpent form, Dahaka will only die after you take out its "head" segment.
 * Nygtilger in Ys.
 * Vaides, the dragon in Dragon Slayer Jr.: Romancia.
 * The giant wiggler from Mario & Luigi: Bowser's Inside Story. Unlike many examples, you have to attack the segments first as its head is invulnerable until all the body segments are turned yellow. Once you do so, the head can be attacked, but only for a short while- the wiggler will turn red again after a few turns, forcing you to repeat the process.

Shoot'Em Up

 * R-Type has long, indestructible worms which coil around the player and seem to be one with the boss, a giant heart.
 * Talk about a bad case of heartworm...
 * Gradius V has huge wormy monsters with vulnerable heads. or tails.
 * A fire serpent enemy from the NES version of Gradius II.
 * Recca had these as normal enemies, as well as sub-bosses. Like most examples they can only be attacked in the head.
 * In the Hunt had a long, ancient fish with a vulnerable head as the Mini Boss of the fourth stage.
 * Bio-Hazard Battle has a few enemies like this. Like many other games, their weak point was usually the head.
 * BIOMETAL had these as regular enemies, as well as the fourth boss.
 * Apidya has an eel like this. Again, only the head can be damaged.
 * Project X
 * The obscure Shoot'Em Up Steel Saviour has these in stage 2, as well as the boss of stage 4.
 * Bioship Paladin has these as Giant Mooks. One of which you will encounter is seemingly indestructible, but actually isn't.
 * Geometry Wars features these.
 * The fifth boss in Super Star Soldier represents this very clearly- the thing is huge and consists entirely of joints, and moves very very fast. The fifth stage also features regular enemies of this wormy type (appearing one and a half minutes into this video).
 * Star FOX Command has quite a few of these, including two bosses. Sometimes all segments need to be shot, sometimes only the head (but shooting all other segments first will give more points).
 * Centipede. Blowing up a segment within the body of the centipede results in multiple centipedes, and individual segments are also mobile.
 * Eliminate Down has the first Mini Boss as one of these.
 * Heavy Weapon has the Mechworm boss, which had its head as the weak point. It also had three segments that tossed out bombs, these could be destroyed, however, destroying all three segments will make the head start using a Macross Missile Massacre.
 * Irem's Dragon Breed and Jaleco's St. Dragon have the player controlling one of these.
 * Shadow of the Ninja had a pair of these as a miniboss in Stage 2-1.
 * The second boss of Wonder Boy III: Monster Lair.
 * The Dragon Laser in Lightning Fighters, a Smart Bomb-like special weapon that flies around the screen obliterating enemies.