Litter Shitter have performed some of the most olfactory/unhygenically extreme performances I've attended.
Sonically/atmosphere/words-wise, Brian Lewis Sander's set at "Extreme Rituals: A Schimpfluch Carnival" in bristol 2012 is the only noise show I've been to that nearly made me physically ill/have a panic attack, tho bit in Dave Phillips' set where there was a sudden move to timestretching, strobes and plants in the audience screaming came close too, thought for a moment I'd been spiked or something :D