Blastworm

The Blastworm is an enemy featured in Spirit Tracks, first encountered in the Forest Temple.

Characteristics
When injured, the Blastworm will roll into a spiny ball that detonates on contact. Link can blow Blastworms about with the Whirlwind to use them as exploding projectiles. This is useful for completing puzzles in the Forest Temple—destroying blocks and activating out-of-reach switches—as Link has obtained neither Bombs, the Boomerang, or the Bow at this point in the game. Blastworms are naturally docile, though they will crawl towards Link if he comes too close.

Blastworms resemble caterpillars or other larvae. In fact, Stagnox hatches them during the second phase of the battle. Link uses this to his advantage, blowing them back at Stagnox to cause damage.