Ban Swagger, Flatter, Confuse Ray, and Supersonic under a Confusion Clause, as well as any virtually synonymous moves I might've forgotten. Same concept as the Evasion Clause, except it plays out a bit differently. You can work around both effects, but they're both often enough just a giant luck mess.
Foul Play, Prankster, etc. are just ways of magnifying the fundamental threat of confusion. They are not the problem. There's no need for a complex ban when we already have a simple ban that fits existing ban philosophy.