8. Aerosmith/Guns N' Roses (1988)
When Guns N' Roses first hit the scene in 1987, some critics derisively labeled them a cheap Aerosmith knock-off. The fact that Guns featured Aerosmith's "Mama Kin" at many of their early shows – and on their debut EP, Live Like a Suicide – didn't do much to shatter this idea. Needless to say, Guns N' Roses eventually forged their own identity and, in the summer of 1988, they hit the road with Aerosmith on their Permanent Vacation tour. Aerosmith was touring in support of a monster comeback album, but the tour was almost overshadowed by Guns N' Roses, since Appetite for Destruction had been flying off shelves all summer long. Despite Axl's chronic misbehavior, the two groups formed a close bond and many of the guys are tight to this day. Check out this video of both groups performing "Mama Kin" in the early 1990s.