From the Super Mario Wiki
Galleom is a boss that appears in the game Super Smash Bros. Brawl. Galleom is a purple skinned monster in a robotic form. Galleom is first fought by Meta Knight, Marth and Ike. After the battle, Galleom takes a huge leap and lands near to where Wario was once turned into a trophy. However, the floor breaks from the impact of the landing and Galleom falls into The Ruined Hall. Galleom then sees Lucas and Pokémon Trainer, and fights them. After the second battle Galleom grabs Lucas and Pokémon Trainer and opens his cranium, revealing a Subspace Bomb. Galleom launches into the air with them having only 15 seconds left, intending to take them with him to his death.
Lucas uses PK Thunder to break off Galleom's arm, and frees them. Right before they land, they are saved by Meta Knight. Galleom, however, meets his end with the explosion of the Subspace Bomb. Later though, players must fight him again in The Great Maze. Although he was fought two times in the game, players only need to fight him once in the Great Maze.
The Galleom trophy is earned by use of a Trophy Stand. To get the trophy of the tank form of Galleom, the player must clear the Boss Battles game mode on Intense difficulty level.
 Super Smash Bros. Brawl Trophy Description
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