OSLO, Norway - A man attending a heavy metal concert (I think Mayhem) suffered a fractured skull when he was hit with a flying sheep head.

The head flew off the knife of Mayhem lead singer Maniac who had just carved up a dead sheep as part of the act.

"My relationship to sheep is a bit ambivalent now. I like them, but not when they come flying through the air," concertgoer Per Kristian Hagen, 25, told the Associated Press from his hospital room.

The concert took place 500 kilometres west of Oslo. Hagen's injuries were not life threatening and he is expected to recover.

He filed involuntary assault and battery charges against the band.

The group said the incident was an unfortunate accident and promised Hagen a free ticket to their next performance.