What it does
Breaking Swipe is a Dragon-type physical move and a spread move in doubles — it hits both opposing Pokémon at 0.75× damage each, and each target that's hit has its Attack dropped by one stage.
That's the hook: one move drops both opposing Pokémon's Attack simultaneously. If both targets are physical attackers, you've halved their offensive pressure in one action. That's two Intimidate-equivalent drops from a single move slot.
Dragon-type hits most things neutrally, but Steel-type Pokémon are resistant (heavily), and the attack drops won't apply to Steel-types either. Check opposing types before committing.
Who runs it
Altaria at 26% uses it as the centerpiece of a support/control role. It's not trying to KO — it's trying to make the opposing physical attackers irrelevant while its partner deals damage. Paired with the Perish Song that Altaria also runs at 49%, the combination forces switches and simultaneously weakens whatever stays on the field.
Goodra at 17% pairs enormous Special Defense with Breaking Swipe to stay relevant on the offensive side. High-bulk Pokémon in doubles often contribute little beyond absorbing hits; Breaking Swipe gives Goodra a reason to attack that also helps the team.
Serperior at 7% adds Dragon-type coverage to a Grass-type, which doesn't hit anything Grass struggles with, but the Attack drops affect both opposing physical attackers and that has team value independent of type coverage.
How to use it
The ideal scenario: both opposing Pokémon are physical attackers. Use Breaking Swipe on turn one — both take chip damage and both lose an Attack stage. From that point forward, their offensive output is reduced, your Pokémon survive longer, and you control the tempo.
Stacking with Intimidate: if your lead already triggered Intimidate when it entered (−1 Attack to opposing Pokémon), and then fires Breaking Swipe (−1 more), both opposing physical attackers are at −2 Attack. That kind of pressure makes physical offense nearly useless.
Against two special attackers, Breaking Swipe's Attack drop does nothing useful. Consider other moves in that matchup.
Tips & strategy
The 0.75× spread penalty means Breaking Swipe hits softer than a single-target Dragon move. If you need to KO one of the opposing Pokémon quickly, a focused Dragon attack hits harder. Breaking Swipe wins when you need both targets weakened, not one KO'd.
Steel-types take the hit but keep their Attack stage. If one opposing Pokémon is Steel-typed, only the other one drops — half the value. Factor that into whether it's worth using.