Trevenant is a ghostly Pokémon resembling a slender brown tree. Its shadowy black body is visible through gaps in the tree, and a single, red eye is visible through a hole near the top. There is a wavy, horn-like branch on either side of its head, both dotted with small, green leaves, and a smaller branch on its forehead. On top of its head is a cluster of green leaves. It has two arms with gnarled branches similar to its horns on the elbows. Around its wrists are cuffs of green leaves and it has three claw-like fingers on each hand. Instead of legs, it has six roots similar to a spider's legs.
Trevenant can control other trees by using its roots as a nervous system. It uses this ability to trap people who harm its forest and will curse people who cut down trees. However, it is very kind to forest-dwelling creatures and Pokémon that reside in its body. Trevenant hates Fire-type Pokémon, so lumberjacks usually bring them to repel it. It is even believed that Trevenant has consumed people, although it is unclear whether this is fact or rumor.
Of all the Pokémon that evolve via trading (including with held items), Trevenant is the only one who can also be directly caught in the wild in the same generation in which it was introduced.
