Puroboros is a fiend in Final Fantasy X encountered in the Omega Ruins after defeating Omega Weapon. Like other Bomb-type enemies, it grows after each attack, and after the third growth (if it has not been defeated), will explode above a random party member, causing 2500 damage. Kimahri can learn his Ronso Rage skill, Self-Destruct, from any of the Bomb-type fiends in Spira.
Puroboros can drop weapons with 3% probability for NTSC version and 4% for PAL. Puroboros has 20% resistance to Dark and Silence (NTSC and PAL versions); and 120% resistance to Death and Petrify (only PAL version).
Despite their threatening amount of HP, they're relatively harmless. One can summon Ifrit to absorb their casts of Firaga, or use NulBlaze. Since they are weak against Ice, a powerful cast of Blizzaga should finish them in no time. Dualcast does not cause the Puroboros to grow, diminishing the threat further.
The Puroboros will drop armor with Fireproof or Fire Eater and weapons with Firestrike. Weapons dropped by Puroboros are slightly stronger than most weapons (they have a Damage Constant of 18, while any otherwise-identical weapon has a Damage Constant of 16); a trait shared with Bomb and Grenades, but not found in Bomb King or any enemy outside the Bomb species.
Pyrobolus is the Latin word for "Bomb".