Breloom@toxic orb or life orb or power herb
Evs: 252attack/152def./the rest in attack
Nature: jolly( +speed -sp. attack )
Ability: poison heal or technician
Spore: it is EXTREMELY busted because it has 100 accuracy and puts the opponent to sleep, that means you can get at least one free hit off, and that hopefully will OHKO the sleeping Pokemon.
Focus punch: The turn the opponent sleeps is the turn you charge up, and the next turn you deliver an OHKO. This is almost certain if it's a neutral hit, as focus punch has a 150 base power ( 225 if stab is included ). It also has perfect accuracy, so this move is basically a death sentence to any neutral or super-effective hit.
Sky uppercut/Mach punch: Mach punch is boosted by both STAB and technician, and it also has priority. Sky uppercut does more damage and also has STAB, but ,no priority. An alternative is drain punch, as it restores breloom's HP.
Seed bomb: good damage and STAB.
All attacks use breloom's awesome attack stat.