zack mennell made a costume out of nappies and waded into filthy waterways saying: 'I'm going to be the parasite.' The performance artist's project became more literal than originally intended On the Deptford foreshore, a ghoulish figure is sinking into the Thames. Performance artist zack mennell (who writes their name in lower case) wades to their belly button as a crowd watches on. DAs they dip down further, their …