Gengar @ Ghostium Z 
Ability: Cursed Body
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
- Hex 
- Sludge Wave / Sludge Bomb 
- Will-O-Wisp 
- Focus Blast

Gengar @ Metronome 
Ability: Cursed Body
EVs: 4 HP / 252 SpA / 252 Spe
Modest / Timid Nature
- Shadow Ball
- Sludge Wave
- Taunt
- Focus Blast

Gengar @ Choice Specs
Ability: Cursed Body
EVs: 4 HP / 252 SpA / 252 Spe
Modest / Timide Nature
- Shadow Ball
- Sludge Wave
- Focus Blast
- Trick

Gengar @ Choice Scarf
Ability: Cursed Body
EVs: 4 HP / 252 SpA / 252 Spe
Timide Nature
- Shadow Ball
- Sludge Wave
- Focus Blast
- Trick