found in Windswept Wastes.
The shell slug acts much like a slug, meaning that it will crawl along the ground or any other flat surface, moving back and forth in a pattern. It will not chase the player upon nearing him or her, but will continue it's original route. When the player come in contact of the slime, they will take half life cell of damage, and unless they move away from the slime, Ori will keep taking damage until their death.
Shell slugs can be instantly killed in contact with water, spikes, lazers, or other hazards. Before it can be hurt by the player's weapons or abilities, the player must first take it's shell off, by either burrow-dashing it from below, or smashing the shell open with a hammer, turning it into a slug. Once it does, the player then can kill it with with three swings of a Torch, a smash of a Spirit Smash, a shockwave of a Spirit Smash, one Spike, three hits of the Spirit Edge, or three arrows of the Spirit Arc.
TThe slug moves slowly,with an animation like inching forward by stretching out and recoiling,like a snail or slug, allowing the player to have the advantage of speed. It is easy to deal with, as it can be killed or avoided as one does to a slug, provided that the player has the Sprirt Hammer or Burrow.