Drummer Hellhammer claimed that Dead “was the first black metal musician to use corpsepaint”, thus being the originator of the most identifiable aspect of the black metal aesthetic. According to Mayhem bassist Necrobutcher:

It wasn’t [sic] anything to do with the way KISS and Alice Cooper used makeup. Dead actually wanted to look like a corpse. He didn’t do it to look cool.”

Dead began burying his clothes days or weeks before a live performance, only digging them up hours before the show. On one occasion he even asked his band mates to bury him alive before a concert so he can look more like a corpse while on stage.

Dead also carried dead, decomposing birds with him while on tour, keeping them in plastic bags. Before a concert, he would inhale the rotting miasma so that he may perform “with the stench of death in his nostrils.” Morbid props, like mutilated pig heads impaled on pikes, adorned the stage for Mayhem performances and Dead made a habit of hurling pig heads at the crowd.

read more about this interesting character here (definitely NSFW and there’s some blood and disturbing imagery)