From: "The Secret Life of Lobsters" via wikipedia

lobsters.txt

The American lobster urinates not from some posterior region of 
its body, but directly out the front of its face. Two bladders 
inside the head hold copious amounts of urine, which the lobster 
squirts through a pair of muscular nozzles beneath its antennae. 
These powerful streams mix with the gill outflow and are carried 
some five feet ahead of the lobster in its plume ... What the 
researchers discovered during the ensuing fights was that dueling 
lobsters accompanied their most punishing blows during combat by 
intense squirts of piss at the opponent's face. What was more, in 
scenes akin to a showdown at the OK Corral, the winner of the 
physical combat almost always turned out to be the lobster that 
had urinated first. And well after the fight was over, the winner 
kept pissing. By contrast, the loser shuts off his urine valves 
immediately.