Galleom

Galleom is a boss that is encountered twice in The Subspace Emissary. It doesn't hail from any particular series and is unique to Super Smash Bros. Brawl.

It is first seen by Marth, Ike and Meta Knight, traveling through a desert in its tank form. After its first defeat, it crashes through the ground and lands in an underground temple, where it must again be fought by Lucas and Pokemon Trainer. After its second defeat, it tries to detonate a Subspace Bomb, but ultimately destroys only itself.