Slither Face is an alchemist from the 22nd century. He was ripped from the roots of the village speaking tree and has no skin.
Slither Face's flesh is a complex melting plastic that shapes and reshapes itself constantly, so that he has no fixed body or facial features. In fact, it is through force of will alone that he maintains a humanoid appearance (e.g. two arms, two legs, two eyes, and a mouth). Over time, it is believed that his will will become so strong that his appearance will harden permanently into a shining pink obelisk, but this is only speculation.