Parasite Cage

The Parasite Cage (パラサイトケイジ) is an Emblem Heartless that is found in Kingdom Hearts and Kingdom Hearts: Chain of Memories. It is one of the bosses at Monstro.

Kingdom Hearts
''Heartless that appeared inside Monstro. It's known to swallow its enemies. Sora and the others rescue Pinocchio, who was trapped inside it.''

Kingdom Hearts: Chain of Memories
A Heartless that dwelled inside Monstro.

''The Parasite Cage is quite the gourmand and eats anything in its path. Pinocchio figured out how to escape Monstro after getting gobbled up by it.''


 * Reverse/Rebirth

''A Heartless that dwelled inside Monstro. It appeared before Riku as a token of the indeliable darkness in his heart.''

Kingdom Hearts
The Parasite Cage was a Heartless sent into Monstro to find and capture the heart of Pinocchio (and possibly locate Monstro's). It captured the puppet when he ran away from Riku. However, before it could succeed in escaping, Riku, Sora, Donald, and Goofy battled it in Monstro's Bowels. Eventually the Parasite Cage spit out Pinocchio and climbed away into Monstro's depths. Despite being defeated, the Parasite Cage retained Pinocchio's heart.

Sora chased Riku into the Stomach, only to discover that the Parasite Cage had lodged itself there. With Pinocchio's heart, the Parasite Cage had increased inside, and had become much more powerful. Sora battled it one last time before it was finally destroyed.

First Incarnation
At the start, remain on your platform and lock on to the Cage’s head, shooting Fira or Gravity spells at it. Keep doing this until it’s beaten and escapes. If you need to recharge, either use an Ether or attack the head and cage with the Keyblade until you’ve regained enough of your MP. After winning, Goofy learns the Cheer ability.

Second Incarnation
This fight is much the same as the last one, but the Cage has developed a new poison breath attack. When the Cage gets tired and sags backward for a moment, it's mouth will open. Bash it with the Keyblade, and Try to execute a couple of flying combos during this time. When it recovers, return to your normal strategy of casting spells at the head. Eventually, it reverts to its old strategy, and the player can get closer to smash it with the Keyblade. After the battle is over, Sora and Donald will learn the Stop spell. The party is then automatically ejected from Monstro and returns to the Gummi Ship.

Attacks
Please note that the names of the attacks are conjectural, as they are never given.
 * First Time
 * Left Tentacle: In which the Parasite Cage swings its left appendage
 * Right Tentacle: In which the Parasite Cage swings its right appendage
 * Double Swing: In which the Parasite Cage connects its appendages and swings them in both directions, characterized for being its strongest attack


 * Second Time
 * Left Tentacle: In which the Parasite Cage swings its left appendage
 * Super Left Tentacle: In which the Parasite Cage swings its left appendage more powerfully (marked by the mandibles at the end shining at the height of swing)
 * Right Tentacle: In which the Parasite Cage swings its right appendage
 * Super Right Tentacle: In which the Parasite Cage swings its right appendage more powerfully (marked by the mandibles at the end shining at the height of swing)
 * Double Swing: In which the Parasite Cage connects its appendages and swings them in both directions, characterized for being one of its strongest attacks
 * Stomach Acid: In which the appendages' mandibles absorb stomach acid from Monstro's stomach and the head fired it as a poisonous gas; best avoided on the ground
 * Swing: In which the appendages mount themselves on the ground and the cage swings into the air; best avoided to the side

Reverse/Rebirth
Since you obtain the Monstro world card within the first few stages of the game, defeating the Parasite Cage is a cinch. The only thing you need to do is successfully fill the Dark Points gauge bar up to 30 by breaking every single card. After that, whack the Parasite Cage with all you've got - simple attacks, sleights, everything! Also note that while Riku is in Dark Mode, HP orbs come out of the Parasite Cage with every attack, so it is easy to heal, and easy to stun the enemy.

Trivia

 * This is the only boss battle in Kingdom Hearts where Sora receives help from an ally not in the party.
 * Parasite Cage's appearance bares many similarities with and possibly based on Prison Cage from Final Fantasy IX.

Notes and References
Parasitocage