Galdon is the first boss of Star Fox Adventures. It appears in DarkIce Mines, having been trapped in a block of ice and accidentally thawed out by Tricky. It fights Fox and devours him, but Fox finds the SpellStone trapped in its belly and retrieves the SpellStone, which kills Galdon for some unknown reason.
He was originally going to be a character in the game Dinosaur Planet prior to the Star Fox overhaul, as revealed by an early screenshot for the game. It can be assumed that the boss battle would've turned out the same way it did in SFA.