When Does Phantump Evolve. Introduced in gen vi, phantump evolves into . There's also a spooky new addition to the pokedex: Just as in previous pokemon games, once you have a phantump, you'll only be able to get its evolved trevenant form when performing a trade. According to old tales, phantump are stumps possessed by . Phantump is a ghost/grass type pokémon introduced in generation 6. The most standard method is to have 200 phantump candy and directly turning it into . Evolve it at your convenience.