Slugs will crawl along the ground or any other flat surface, moving back and forth in a pattern. It will not pursue Ori upon nearing them. When Ori comes in contact with them, they will take a life cell of damage, and unless they move away from the Slug, Ori will keep taking damage until their death.
It is possible, though unlikely, for the slug to fall or bump into hazards when moving in said pattern. This can be caused by the player bashing it into an area near a hazard.
Slugs have 18 health points and can be instantly killed in contact with water, spikes, lazers, or other hazards. They can also be killed 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, and can be bashed.
The slug moves slowly, inching forward by stretching out and recoiling, like a snail or slug, allowing the player to have the advantage of speed. If the player is well-equipped, the slugs do not pose much of a threat, but as they are found in the earlier stages of the game, they pose as a moving hazard to the player, as the player cannot attack at that time. However, the player can easily avoid them at this stage, by either jumping over them, or waiting for them to past.
Slugs will yield five to ten Spirit Light upon death.