Gastly

Gastly is a dual-type Ghost/Poison Pokémon that first appeared in. It evolves into Haunter starting at level 25, which evolves into Gengar when traded.

Gastly appears in Super Smash Bros. for Nintendo 3DS as a Smash Run enemy. As it is engulfed in poison gas, it is immune to melee attacks and can only be taken out with projectiles. It can damage players in contact and will sometimes follow him/her.