On my Mega Gengar in Balanced Hackmons:
Gengar @ ???
Ability: Speed Boost
EVs: 252 HP / 252 Def / 252 SpA / 252 SpD / 252 Spe
- Moongeist Beam
- Ice Beam
- Secret Sword
- Protect / Spiky Shield / Baneful Bunker / King's Shield
Also any ideas for its item would be appreciated too!
Either Spiky Shield or Baneful Bunker. Protect doesn’t have any added effects and King’s Shield doesn’t block status moves. I would personally rank Spiky Shield higher, but Baneful Bunker is also a good option.
For the item, it’s hard to go wrong with Life Orb. I would recommend using a Modest nature instead of Timid because after 1-2 turns, you’re going to be outspeeding everything regardless.