The musician, 80, read out pages of notes about a mole that had been developing near his genitals, including a worry that it would 'start annexing [his] stuff if left unchecked'. The improvised dermatology session lasted for 20 minutes - leaving audience members stunned.
Fans became enraged, eventually starting dueling chants of 'let's go d*** mole' and 'd*** moles suck', bouncing multiple beach balls around and generally getting rowdy after almost half an hour without any indication that the artist was going to sing a song.
The conflict came to a head when Waters invited an audience member to come on stage and tell him 'if it looked like melanoma'. The fan got on stage, looked at the singer's mole and genital region, threw up, then told the singer to 'f*** off and ask a doctor'. Waters immediately left the stage afterward, completely red with embarrassment, shuffling with his pants at his ankles like a little crab.
It is not clear why the fan went to look, only that what they saw was concerning enough to warrant a visceral reaction. For Waters' sake, hopefully it wasn't the mole that made them puke.
