Pennysmart

Introduced in The Science of Discworld III: Darwin's Watch, Dr. Pennysmart is the Professor of Extreme Horticulture at Unseen University. He comes to grief in an accident involving an affronted jellyfish and is last seen carried off on a stretcher, screaming in agony, with legs that have turned an extremely interesting shade of purple. Evidently being Professor of Extreme Horticulture does not involve any sort of academic training in exotic poisonous sea creatures, specifically their recognition and avoidance. Although why should it, as horticulture relates to plants, not (in any way, shape or form) to aquatic zoophylae.