Basically:
-The singer for Mr. Bungle, Mike Patton, was in Faith No More and when Epic came out Kiedis thought he was biting him. They took shots at each other throughout the 90s
-In 1999 when Californiacation came out, Mr. Bungle put out an album called California. Kiedis thought Patton was biting him again and (allegedly) got Mr. Bungle removed from different European performances that RHCP was going to headline
-Mr. Bungle then got mad and played a Halloween show where they dressed up as RHCP members (and some dead members/affiliates of the band like Rivers Phoenix), covered their songs, made a bunch of heroin jokes etc.
-Kiedis lost it and got them removed from a much bigger festival in Australia. They broke up like a year later
rock beef