The Nice burning the american flag(not that I'm patriotic or anything but still it's pretty outrageous).
Keith Emerson(of the Nice and later ELP)throwing knives into his organ(the musical instrument
).
Jimi Hendrix burning his guitar at Monterey music festival(circa 1967).
Pete Townshend smashing his guitar on numerous occasions(mostly in the early days).
Ozzy Ozbourne biting the head off of a bat(he claims he didn't know it was live and thought it was fake; I believe he was subsequently treated for rabies after that incident).
Alice Cooper decapitating fake dummies(they were fake but still having a guillotine on stage is pretty outrageous).
Rolling Stones(probably Mick's idea)having a giant phallus on stage(not sure when but I think around 72,73). They might have been the world's horniest rock band.
Iggy Pop stabbing himself on stage circa 1973
I'm sure Kiss and Marylin Manson have done stuff that deserves to be mentioned.