Randomly KOs a _target.Description
Roulette is a Blu Mag spell for Quina in Final Fantasy IX that inflicts KO to a random _target in the battle, be it enemy or ally or even undead, at a cost of 20 MP. Roulette cannot be reflected and is programmed to respond to Return Magic, however, if the "roulette wheel" lands on the character with Return Magic, they are simply killed. Hecteyes, Veteran, and Zombie use it against the player party.
Obtain
Quina learns Roulette by eating a Ghost, Zombie, or Hecteyes. The earliest it can be learned is after the party has the Blue Narciss, and then heading to the areas outside Treno or to the Iifa Tree to find Ghosts and Zombies. The easy way to eat either is to first use a Phoenix Down on the enemy; majority of the time this leaves them at single-digit health, but 10% of the time, it kills them outright.
Mechanics
Roulette instantly defeats the _target it lands on, but the outcome is random. It fails on Heavy _targets, but kills the regular undead, unlike the other Instant Death spells in the game.
Use
Roulette is barely useful as it is exceptionally rare for an enemy formation to include four enemies, meaning the odds are always stacked against the player's four-member party and it is not possible to become immune to Instant Death in Final Fantasy IX. All other instant-defeat abilities are usually superior: Zidane and Amarant's Masamune's Soul Blade and Countdown, Vivi's Death, Break, and Stop, Dagger's Odin, and Quina's Doom, LV5 Death (if the enemy is on a suitable level), Mustard Bomb, and Frost, though the latter needs one more hit to shatter the frozen _target.
To stack the chance to the player's favor, the party would need to have some KO'd allies, or Freya needs to be airborne amid using Jump. However, there always remains the possibility that Quina will KO themself using Roulette. As Yans are highly dangerous, prone to KO'ing a lot of the party, and are best defeated with Instant Death, and Quina's Mustard Bomb has poor accuracy, a three-member Yan battle may be one of the only times the gamble is worth it.
Roulette's one unique trait is that it works on the undead. The enemies that use it may end up killing themselves. However, against undead enemies the player can simply use a Life spell for a superior result.
Etymology
Russian roulette is a potentially lethal game of chance in which a player places a single round in a revolver, spins the cylinder, places the muzzle against their head, and pulls the trigger. "Russian" refers to the supposed country of origin, and roulette to the element of risk-taking and the spinning of the revolver's cylinder being reminiscent of spinning a roulette wheel. As only one chamber is loaded, the player has a one in n chance of hitting the loaded chamber, where n is the number of chambers in the cylinder.