What is this sport called exactly?

I'm a noted Internet slapfight enjoyer so this seems like it should be in my wheelhouse

https://s3.us-east-1.wasabisys.com/cdn.seal.cafe/fdd330297cbe9237d42b60fa7e8188184f493ce7d5cd81baa746adc844209a40.mp4?name=KdiSJdrJwYZxsQ.mp4