Bam Margera -- Knocked Out After Brutal Attack (VIDEO)

Bam Margera was viciously attacked in Iceland Saturday at the Secret Solstice Festival.

A festival spokesman claims the "Jackass" star was in a "really weird condition" and tried strong-arming his way into the production room. The spokesman says Bam started heckling 2 women who were blocking him, and that's when the went lights out.

Bam claims it was quite the opposite ... he says the attack had nothing to do with the 2 women, and says he was brutally attacked by "a scumbag" who helps run the festival.