The only correct answer here is Yoko Ono and her Plastic Band. (I'm half kidding.)
Respectfully, I don't at all agree with Nick's assertion that Nirvana truly did damage to a genre or music in general. I don't at all enjoy Nirvana but I push back strongly against those kinds of claims. Even Temple of the Dog, Soundgarden, etc... as much as I cannot stand them, I don't think they were a 'negative force on music' or anything like that.