It was recently announced that Alice Cooper and Marilyn Manson would be touring together  (more details), and while some might think it's an odd paring because of the difference in eras, it does make sense.  Obviously Marilyn Manson took his cue from Alice Cooper's antics in the 70's.  In fact Alice was the first to really take "shock rock" to an arena sized audience.  Anyone who's put on makeup (including Kiss) owes a debt to Alice for paving the way and desensitizing the mainstream to a certain extent.

Here's a little reminder of how twisted and bizarre and unnerving his performances could be.  He implemented more of a sense of humor later in his career, but back in 1973 he was really came across as a mental patient out for the weekend.

Alice Cooper - "I Love The Dead"

Manson took Alice Cooper's dark side to a new level as he attempted to be more shocking and more controversial.  The main difference between Cooper and Manson may be the fact that Alice was eventually able to separate himself from the "character" of Alice.  We're still waiting for that to happen to Manson, from all accounts he's as crazy as he is on stage.

Marilyn Manson - "Beautiful People"