ghost
Dark type can beat ghost.
Psychic
Fighting and bug type moves are super effective against the dark type.
any dark type move
Dark and ghost type moves.
I would choose a Dark or Ghost type
Bug, Ghost or Dark.
A freaking dark type. It is not like he is invincible!
Pokémon types that can beat Psychic-type Pokémon are Dark, and Bug. Ghosts however lose against Psychic.
Using Dark or Ghost type moves against it
Psychic type Pokémon usually.
Heres one for ya ghost types