What it does
Belly Drum costs half the user's maximum HP and raises Attack to +6 immediately. +6 Attack is a 4× multiplier on whatever your base Attack already was. If your HP is too low to pay the cost, the move fails.
The payoff is absolute: after Belly Drum, nearly every target in the game is in one-hit KO range from a physical move. Walls that would tank normal hits can't survive. Setup that usually requires multiple turns is skipped entirely — you go from base attack to maximum attack in one move.
The cost is equally extreme: you're left at half HP, fragile to priority moves, spread damage, and anything fast enough to move before you. Belly Drum only works if you can survive long enough to actually swing after setup.
Who runs it
Azumarill (74%) is the definitive user. Huge Power doubles its Attack stat, so Belly Drum×Huge Power together reach an extreme number. The critical piece is Sitrus Berry: Belly Drum drops HP to 50%, which immediately triggers Sitrus Berry to recover 25% of max HP — net cost is only around 25% HP, but Attack is at maximum. That's what makes the play viable rather than suicidal. The weakness is Speed 50, which means Azumarill almost always needs Trick Room or a partner's Fake Out setup window to use Belly Drum safely. After setup, Aqua Jet's priority bypasses the speed problem.
Snorlax (23%) takes the opposite approach on bulk. Its base HP is enormous, so even at half HP after Belly Drum, the actual remaining HP is still high — it can take several hits before going down. Speed 30 means it runs under Trick Room and moves first in the reversed priority. Multiple turns of +6 Attack swings after setup, rather than Azumarill's one-or-two burst window.
How to use it
You need a protected setup window: Using Belly Drum directly into two attackers is a KO risk — your HP goes to 50% on their turns. The most stable route in doubles: a partner uses Fake Out on the bigger threat turn one, Azumarill uses Belly Drum safely, turn two it starts swinging at +6. This 'Fake Out into Belly Drum' opener is one of the most established doubles setups because no equivalent option offers the same safety.
Sitrus Berry timing: On Azumarill, Belly Drum triggers Sitrus Berry immediately on the same turn. The Berry is consumed once and won't trigger again — make sure it hasn't been Knock Off'd or eaten before you need it.
Snorlax under Trick Room: Speed 30 becomes the fastest under Trick Room. Belly Drum on turn one, then move first each subsequent Trick Room turn. With Snorlax's massive raw HP, even at 50% it can absorb hits and swing multiple times. Building around a dedicated Trick Room setter is mandatory for this to work.
Tips & strategy
After setup, hit first: At half HP with +6 Attack, hesitation kills you. Move fast, target the biggest threat, and don't protect unless you're certain the opponent can't reach the KO this turn. The window is short.
Priority moves are the hard counter: Aqua Jet on Azumarill specifically solves the opponent's priority counter — it hits first regardless of Speed. Snorlax doesn't have priority, so it's more exposed to priority revenge-kills. Identify the opponent's priority users and make sure you can handle them before committing to Belly Drum.
Singles is riskier: No partner to absorb hits means Belly Drum has to be done behind a Protect turn or a situation where the opponent literally can't attack you this turn. Against any opponent that knows your plan, singles Belly Drum is much harder to execute safely than doubles.