Leviathan grub

Leviathan grubs were a subterranean, omnivorous species native to the moon Yavin 4. The grubs would feed on the roots of Massassi trees below ground for three hundred years before emerging as one of the largest predators in the moon's forests.

Behind the scenes
Leviathan grubs were first mentioned in the reference book Ultimate Star Wars, which was released in 2015.