Game:Monstro

Monstro is introduced as a boss in Kingdom Hearts Birth by Sleep Final Mix, after appearing as a world in Kingdom Hearts and Kingdom Hearts: Chain of Memories. He is fought within the "Monster of the Deep" battle in the Mirage Arena.

Development
Monstro was not the original choice for an additional Disney Boss for Kingdom Hearts Birth by Sleep Final Mix. A Square executive originally suggested having one of the Titans appear, but as they'd already included the Ice Colossus, they opted for an alternate boss similar in size, resulting in Monstro appearing instead.

Strategy
The battle begins inside Monstro's stomach, where the protagonist will be faced with a squad of Unversed which must be defeated in order to get Monstro to sneeze the player above the surface of the ocean.

Once outside, a three-minute timer will start counting down, in which the protagonist must deal as much damage as possible to Monstro before it runs out, though it can be tricky due to Monstro's mobility and the scarce attacking ground. Monstro will occasionally slam his tail on the arena, dive across and even try inhaling the player to sneeze them out and deal damage. The main strategy of the battle is to hit Monstro as many times as possible with the explosive barrels while he is swimming slowly. Once hit enough times, Monstro will go dizzy and leave his tongue hanging out, a sign for the protagonist to get close and use a Shotlock, possibly twice if quick enough. Occasionally, Monstro will slam his upper body onto a small island and briefly leave himself open to melee attacks.

If the timer runs out, Monstro will automatically swallow the protagonist again, facing them with another squad of Unversed; each time the protagonist returns, the amount of stomach acid increases, leaving less area to fight. The final round occurs after the fourth time the protagonist escapes, and will have no timer.