I'm curious to know if anyone's ever tried a Choice Banded Ninjask. It seems with all the swellows out there that have Choice Band Ninjask has higher Attack & Speed... might work well. Although, I know Swellow has a few other things going for it like STAB for normal attacks & the Guts ability.

I figure something like...

Shadow Ball
Silver Wind
Aerial Ace/ HP Flying
Return

Or something like that above...

I wonder if it could OHKO a Gengar with Shadow Ball.