Megadeth cut their set short at Metalfest 2012 in Croatia after frontman Dave Mustaine was hit in the head by a rock thrown by an angry fan.

Fans chanted "We want W.A.S.P." during Megadeth's performance after a rumor spread in the audience that Blackie Lawless of W.A.S.P. refused to perform at the event following an argument with Mustaine. Whether an argument between the two actually occurred has not been confirmed.

Here's the video...

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