Trevenant @ Choice Band  
Ability: Natural Cure  
EVs: 252 Atk / 4 SpD / 252 Spe  
Adamant Nature  
- Poltergeist  
- Wood Hammer  
- Rock Slide  
- Shadow Claw / Sucker Punch  

Trevenant @ Assault Vest  
Ability: Natural Cure  
EVs: 208 HP / 252 Atk / 48 Spe  
Adamant Nature  
- Horn Leech  
- Poltergeist  
- Shadow Claw  
- Sucker Punch  

Other options: Grassy Glide on Grassy Terrain teams, Substitute+Sitrus Berry with Harvest