Riddling Sphinx

In Classical Mythology, Oedipus encountered a Sphinx and was, famously, forced to solve the Riddle of the Sphinx in order to pass. Ever since, it's been a tradition that all sphinxes ask riddles. So if you see a sphinx, be prepared for a game of Riddle Me This.

The classic Riddle of the Sphinx still appears occasionally, but most sphinxes will come up with their own new ones, since, let's be honest here, everyone knows the answer to the original.

Sub-Trope of Riddle Me This. Related to Only Smart People May Pass.

Film - Live-Action

 * Mirrormask has gryphons and sphinxes, which are similar catlike creatures with human heads, but mixes up their properties. In the film, a gryphon guards the area known as Giants Orbiting, requiring Helena answer the classic Riddle (she succeeds by giving a literal answer) and stump him in return (she gives him something unsolvable and sneaks off while he's thinking about it). Meanwhile, the 'sphinxes' are ravenous beasts which speak seldom and pounce on anyone who seems vulnerable.

Literature

 * In Harry Potter, Harry encounters a sphinx in the hedge maze and has to answer a riddle in order to pass by it safely; however, she does tell Harry that if he decides not to give an answer and just retreat, she won't stop him. She's also generous enough to repeat the riddle a second time when he needs to listen to it closer. Fantastic Beasts and Where to Find Them states this as the reason the sphinx is classed as a beast rather than a being, as it only speaks in riddles and puzzles and reacts violently if given the wrong answer.
 * Percy Jackson & the Olympians: When the half-bloods meet a sphinx in the Labyrinth in Battle of the Labyrinth, it tries to administer a multiple-choice standardized test, with mundane trivia questions. Annabeth, who was expecting a riddle that would test her cleverness, is not amused.
 * In Pyramids, a sphinx asks Pteppic the Riddle of the Sphinx. Pteppic nitpicks the metaphor and manages to leave the sphinx confused enough that he can make a quick getaway.
 * The Southern Oracle in The Neverending Story is protected by two sphinxes who petrify anyone who fails to answer their riddles.

Tabletop Games

 * This is a standard theme for sphinxes in Magic the Gathering:
 * The original sphinx, Petra Sphinx, had players guess the top card of their libraries. This same guessing game was also used for Conundrum Sphinx.
 * Sphinx of Uthuun gives your opponent choice of which cards to put into your hand.
 * Isperia the Inscrutable rewards you if you can correctly guess a card in your opponent's hand. Of course, since they have to reveal their hand if you guess wrong, the riddle is a lot easier the second time.
 * Sphinx Ambassador secretly chooses one of your opponent's creatures, and if they can't guess which one, you get to steal it.
 * Even sphinxes who don't have riddle-related gameplay will often reference riddles in their Flavor Text, because hey, that's what sphinxes do.
 * In the Test of Metal novel, Tezzeret's attempts at solving riddles left by the mad sphinx Crucius are a major plot point.
 * Dungeons & Dragons:
 * There are multiple subspecies of sphynx, of which the gynosphinx is the most like the Greek one. One supplement lists potential riddles for her to use. One riddle, which she uses when she's too hungry to play fair, has the answer "Kill me."
 * Module I3 Pharaoh. Inside the tomb of Amun-re the PCs can encounter an androsphinx who offers to play a Riddle Me This game with them. If they can answer one of his riddles he will answer a question from them about the tomb. Riddles he can ask include the Riddle of the Sphinx or a Knights and Knaves (Group A always tells the truth and Group B always lies) logic puzzle.
 * The gynosphinx is not present in the 4th Edition, but there are sphinxes with magical powers that make games of riddles more dangerous. A normal sphinx (presented as a guardian of tombs and sacred areas) is bound to ask a riddle and let intruders pass if they can answer it. However, if they answer wrong, the sphinx becomes stronger. In game terms, it gains a temporary bonus to its attack rolls, defenses, one action point, and a second use of a powerful ability it can use to heal itself.
 * The sphinx mystery is an even deadlier creature that is much like the gynosphinx (often challenging prey with riddles for fun instead of attacking outright). One powerful supernatural ability she has (called "Riddle Me This", appropriately) is a mild curse that causes mental damage to a victim if he doesn't at least try to answer her riddle once per round, and does not end until he tries to answer it. If the victim gets help from an ally, the spell is broken, but he takes damage one last time. The Game Master doesn't even need an actual riddle; the victim needs to make a History Skill check to solve the riddle. While a wrong answer will end the curse, it also gives the sphinx mystery the ability to reuse a very powerful physical attack called Corrective Mauling; given what the usual penalty for a wrong answer is, this clearly gives her an advantage. Also, a sphinx mystery is under no real obligation to let a victim go if he answers correctly; Riddle Me This is an At Will ability that it can even use while fighting, so in theory, it could ask riddles over and over again during combat. However, the source does say that it might not attack at all if a potential victim simply plays along and answers them.
 * In the Spelljammer setting, an astrosphinx is a malevolent and insane type of sphinx who asks riddles to anything it sees (even unintelligent animals and plants) killing anyone who refuses to answer or answers wrong. The riddles it poses seem to make no sense whatsoever (like "What is the speed of blue?" "How loud is down?" "What do a kobold and the Spelljammer have in common besides triangles?") and they have been known to destroy all life on entire planets this way. Legend states that it is possible to answer one of these riddles correctly by giving equally-absurd answers, but the chance is slim (1% chance of success). Supposedly, if the astrosphinx's riddle is answered correctly, it will immolate itself in an explosion of burning lightning and leave behind a clue to the whereabouts of the Spelljammer itself.
 * The Yu-Gi-Oh card Ordeal of a Traveler forces your opponent's monsters to win a guessing game if they want to attack you; the art depicts a traveler being questioned by a sphinx.
 * The sphinx depicted is Guardian Sphinx, which has a slightly similar "return monsters to the hand" effect; in the video game Yu-Gi-Oh! World Championship 2008, the player has to solve Duel Puzzles with the Sphinx as their opponent.

Theatre

 * Oedipus the King is the Trope Maker, making this trope Older Than Feudalism.

Video Games

 * Wario Master of Disguise has a sphinx as the boss of the third level. It asks you a series of questions, and if you answer them wrong, it kills you.
 * Fantasy Quest: A Sphinx leaps into your path and asks you a riddle. Unless you're playing the original, console game, you get to choose your answer from a list, so this is one of the game's easiest portions.
 * In the Mystery Land board of Mario Party 2, Bowser is cast as the Bowser Sphinx (though he merely wears an Egyptian headdress and isn't winged or lionlike at all) who challenges all comers to identify a silhouette. The Superstar of the board identifies it easily.
 * One of the tasks in Shadowgate is to give a Sphinx three objects that answer three riddles he gives.
 * Chrono Cross has a Sphinx optional boss that you can beat through straight combat, or by correctly answering its riddles by hitting it with the proper color elements. The order of the answers to the riddles is the same as the order you need to use elements in the final battle to get the True Ending... not that there's any indication of this.
 * There's a sphinx in Super Mario Odyssey that asks Mario, "What does the monster want from this kingdom?" with the multiple choice options, A. Water, B. Wood, C. Flowers, or D. Soil (When Mario gets it right, the Sphinx admits, "Perhaps that wasn't much of a riddle" and lets him by.)
 * It shows up in several other kingdoms after you beat the main storyline, with a few better ones.

Webcomics
"Nodwick: The answer [to the riddle] was "money", by the way. Yeagar: Weren't you paying attention? The answer is always money!"
 * Gastrophobia features a sphinx who is repeatedly humiliated because she only knows the one riddle, and everyone, even the little kid, knows the answer already.
 * The party of Nodwick encounters a riddling sphinx in a dungeon. They bribe it to let them pass, even though Nodwick knew the answer.


 * Phix in Wapsi Square sets the same riddle to both Monica and Shelly as a test to see if they're ready to fix the Calender Machine. They each give different answers and Phix rewards them both - without, however, saying that either answer is right.
 * The protagonist in Mixed Myth runs afoul of a sphinx early on in the story. The answer she gives sounds like it should be right, which causes the sphinx to realize that it's been so long since someone got it right that she's forgotten what the right answer is, so they'll have to head back to her home to check the answer (our heroine is wrong, but gets points for creativity, which lets her off the hook since she managed to endear herself to the sphinx on the journey).

Western Animation

 * In an episode of Superfriends, the sphinx asked Batman and Robin, "What builds up castles and tears down mountains, makes some men blind and helps others to see?" The answer was "sand". The sphinx was a Sore Loser and attacked them anyway, but they quickly defeated it.
 * In Sabrina the Animated Series, a sphinx asks Sabrina the Riddle of the Sphinx. Sabrina answers "Man." Unfortunately, as it turns out, there's a magical nine-legged creature that fits the riddle a bit more literally.
 * In an episode of Disney's |Hercules, the Sphinx is a quizmaster, voiced by game show host Wink Martindale. His riddle was "What does a man do standing up, a woman sitting down, and a dog on three legs?" The answer is.
 * A Noodle Incident from the 2017 reboot of Duck Tales; according to Santa Claus, Scrooge was once able to outwit the Sphinx by convincing her to give them her riddle via multiple choice.