OMG. Fighting Mushroom.

Pros:
+ Attack stat that matches Machamp
+ SPORE
+ STAB Focus Punch
+ Resists Ground and Rock.

Cons:
- Low Speed
- 4x Weak to Flying
- Not a very wide movepool
- Gengar owns it

Ok so:

Breloom (M) @ Leftovers ** Sporeloom
Trait: Effect Spore
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Spore
- Focus Punch
- Substitute / Leech Seed / Hidden Power [Ghost / Bug] / Mach Punch / Swords Dance
- Mach Punch / Leech Seed/ Hidden Power [Ghost / Bug] / Substitute / Swords Dance

Basic and Standard. Watch out for Sleep Talkers.

Breloom (M) @ Leftovers ** Charmloom
Trait: Effect Spore
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Charm
- Focus Punch
- Mach Punch
- Spore

OMG. FORCES SWITCHES. Use with Spikes + a Gengar Counter. People will assume Spore and switch to a SleepTalker. Charm on their switch. This thing still can live through an HP Fly so switch if it is coming but still. Heracross, Lax, ect. look a lot less violent with a big -2 next to their attack.

That second Breloom is amazing. -2 Atk on the HeraSwitch..they aren't going to keep that in. Keep the opponent switching...it is a great set.

I'd use HP Bug/Ghost > Mach Punch for the obligatory Gengar/Celebi switch

lol I saw a CBloom once:

Breloom (M) @ Choice Band
Trait: Effect Spore
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk) or Jolly Nature (+Spd, -SAtk)
- Hidden Power [Ghost]
- Mach Punch / Focus Punch
- Sky Uppercut
- Sludge Bomb

Stun Spore is usable, after you Spore something you can Stun Spore the incoming Salamence switch in or whatever.