No, I don't understand this one. He was sitting - with his trident - on a float somewhere near the FedEx and USPS place on campus, looking fairly jolly, but not contextualized in any way. If it had been early on November 5th (but it was the 7th) and in England (but it wasn't), I might have concluded that it was a guy - that is, a stuffed and dressed dummy, not a male person - getting ready to be burned on top of a bonfire for Guy Fawkes night. If, on the other hand, it'd been a few days earlier, I might have thought that USC had had some Day of the Dead procession, with this zombie-like being riding in mocking triumph. As it is, I think it's just one of those baffling things that one encounters on a campus.