The biggest obstacle to wormfish evolution was their inability to breathe air. Once this had been overcome, wormfish were free to evolve into a multitude of new forms.
The serpentwyrm strongly resembles a tree snake, except for the apparent lack of a head. In actuality, there is no head, only a mouth and a pair of ear-like organs. It also lacks scales.
The serpentwyrm hunts small animals that live in the trees. Its mouth can engorge, allowing the serpentwym to swallow animals much larger than itself.
Serpentwyrms inhabit a variety of biomes, and fill a correspondingly large number of niches. The most common variety, however, is a small arboreal predator.