High Attack, decent Speed, and access to the only 100% accurate sleep-inducing move instantly makes Breloom a force to be reckoned with. Its Fighting / Grass typing is a really great offensive typing, allowing Breloom to defeat 4 of the 5 Pokemon with weather-inducing abilities, though it opens it up to manhandling by Flying-types. Two great abilities further cement Breloom's status as a threat to any team in VGC 2012.
Spore is the only 100% accurate sleep move in Pokemon, and thus it forms the core of this set. With Spore, Breloom is able to incapacitate Pokemon with impunity. The lack of Sleep Clause allows Breloom to put an entire team to sleep. Seed Bomb gives Breloom a reliable STAB move, hitting common Pokemon such as Politoed and Gastrodon for super effective damage. Breloom has two move choices for its other STAB option. Drain Punch hits hard and restores Breloom's HP every time it hits, but Mach Punch has priority and can aid Breloom when it would normally move after the foe. Protect, a move commonly seen in VGC, shields Breloom from attacks for a turn and gives Breloom's partner a chance to dismantle a threat. Protect also activates Toxic Orb if used on the first turn.Team Options & Additional Comments >>>
Rock Slide can be used to dent Flying-types, though most Flying-types in VGC are faster and are able to wipe Breloom out anyway. Substitute used in tandem with Focus Punch, Spore, and Leech Seed could produce devastating results; though keeping a Substitute up for very long is often difficult in VGC. Sky Uppercut has greater power than Drain Punch and, unlike Focus Punch, doesn't require a turn to charge, although its low 90% accuracy and inability to restore HP keeps it from being a primary option. Brick Break is a gimmicky option if one is worried about the use of Reflect and Light Screen, but Drain Punch's healing powers outclass it in nearly all aspects.
A set focusing on Speed could be utilized, where one would take the HP EVs and transfer them to Speed. Additionally, a Speed-reliant set would require the use of a Focus Sash, as the loss of HP would greatly decrease Breloom's ability to take a hit. If this is the case, Effect Spore should be used as the ability to provide a chance to incapacitate the opponent. A Choice Scarf could be utilized to allow Breloom to get off a fast Spore, although being forced to repeatedly use Spore on already sleeping targets is a rather unattractive option.
Checks and Counters
Flying-types wall Breloom with ease, taking little from both of its STABs and hitting back hard with a 4x super effective Flying move. Zapdos and Tornadus are two of the main offenders; Tornadus utilizes Acrobatics and Zapdos, while rarely using a Flying-type move, has a super effective Heat Wave or Hidden Power Ice to destroy Breloom. Fire-types such as Chandelure and Arcanine counter Breloom as well; Chandelure takes no damage from Drain Punch and Arcanine neuters Breloom's strength with Intimidate while utilizing its STAB to burn Breloom to a crisp. Yanmega and other Bug-types are able to take on Breloom with their resistances to its moves and ability to hit hard with a STAB attack of their own. Abomasnow can KO Breloom with a STAB Blizzard, but it must be on the lookout for a super effective Fighting move headed its way. Latios takes anything Breloom can throw at it and OHKOes with a STAB Psychic-type move.
Breloom receives Technician from the Dream World, and were it released, it would turn Breloom into even more of a powerhouse, as Technician-boosted Mach Punch and Bullet Seed would increase Breloom's damage output tremendously. Unfortunately, Game Freak has not yet seen fit to release Breloom in tandem with this stellar ability.