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Can you remember what any of the characters look like, or maybe the general genre of the show? In episode 3 of Revolutionary Girl Utena, Nanami gives Anthy a dress that dissolves when it gets wet and purposely has someone spill champagne on her, but it's a pretty old show by now and it's a ballroom/dance setting, not really a competition.

Longshot but here goes..Was from at least several years ago. Pretty sure it was a female MC. One episode they were having some kind of school contest and one of the other characters was trying sabotage MC by making the her dress(swimsuit?) see through/dissolve when it was exposed to sun(water?). Dont remember if the plan actually succeeded.