Musharna @ Mind Plate/Colbur Berry
Ability: Synchronize
EVs: 248 HP / 252 SpA / 8 SpD
Modest Nature
- Psychic
- Future Sight
- Signal Beam
- Moonlight
As
Winter's Howl already posted, Psychic type's are a great asset for this core. Offensive Future Sight Musharna is a sick partner for Scyth + Chan, as not only can Mushy immediately OHKO any Poison type that would otherwise wall the core, but can actually prevent any of these Poisons from coming in due to Future Sight. With a looming 120 BP Future Sight in the air, bulky poisons such as Weezing and Garbodor can no longer switch in to wall Scyther/Hitmonchan, and your opponent must now switch in something else to try and take a LO Drain Punch from Chan or a +2 Aerial Ace from Scyther. Musharna also appreciates the free switches Scyther provides with U-Turn, and Hitmonchan's ability to break down Steel Types like Steelix that give Mush trouble.
Edit: Mind Plate is cool for the extra boost on Psychic/Future Sight, but in a Sawk infested meta like this one, Colbur Berry is a viable option for extra insurance.