What it does
Soundproof makes the holder completely immune to every sound-based move. Not resistant — immune. The move connects, nothing happens.
The list of blocked moves is long: Hyper Voice, Boomburst, Perish Song, Parting Shot, Roar, Growl, Sing, Supersonic, Round, Echoed Voice, and more. In practice, the one that matters most competitively is Parting Shot.
This is the big deal: Parting Shot is a sound move. Incineroar's standard support loop — enter, Intimidate, Fake Out, Parting Shot out while dropping the target's Attack and Sp. Atk — simply does not work against a Soundproof user. The Parting Shot fires, lands on the Soundproof holder, and does nothing. Incineroar still switches out, but gets nothing in return. That's a wasted turn and a disrupted gameplan.
Perish Song is also nullified, which shuts down the stall-and-swap Perish trap entirely.
Soundproof is a pure defensive immunity — no attack boosts, no speed changes, nothing offensive. It only negates that one category of moves.
Who runs it
Kommo-o is the headline user at 68%. Its case is compelling: it's already a self-sufficient setup sweeper with Clanging Scales or Clangorous Soul, and Soundproof gives it a built-in answer to Incineroar — arguably the single most common Pokémon in the Champions format. Removing Parting Shot from Incineroar's toolkit disrupts the pivot-and-support loop that many teams rely on.
Bastiodon appears at 28%, mostly leaning on its huge physical and special bulk. The Soundproof is mainly to prevent being forced out by Roar.
Abomasnow (1%) barely registers here — the Hail-setting ability set is far more common, so this usage is niche at best.
How to use it
Position Kommo-o to be on the field when Incineroar comes in. That's the core interaction. The moment Incineroar tries Parting Shot and gets nothing, the opponent has to spend a turn recalibrating, which is a meaningful tempo loss in doubles.
Against Perish trap teams, you can just stay in. Kommo-o ignores the countdown entirely and keeps building with Clangorous Soul while the opponent waits for a timer that never forces you out.
One thing to be clear on: Intimidate itself (the entry effect) still works. Kommo-o's Attack still drops when Incineroar enters. Only the Parting Shot move is blocked — but that's still a significant piece of Incineroar's value proposition gone.
Tips & strategy
The matchup reward is highest when you predict the Incineroar switch-in. Many opponents hold Incineroar back and bring it in to pivot out of a bad spot. If you get Kommo-o on the field right as Incineroar comes in, the failed Parting Shot wastes both the turn and the switch.
Don't build around Soundproof as your only answer to support Pokémon. Parting Shot being blocked is strong, but Kommo-o still has to deal with Intimidate's attack drop, Fake Out flinch, and all the other tools opponents bring. The immunity is a complement to Kommo-o's kit, not a complete counter to Incineroar.