Like B. Kliban said: never eat anything bigger than your head. Unless you're a great swallower, that is.
A fisherman from Grand Cayman island found a small great swallower floating on the surface with a much larger whole fish in it's stomach. Four times bigger than the great swallower.
The great swallower is a deep sea fish with a huge jaw and a balloon stomach. Known for eating huge prey, this looks like record catch for a great swallower. Of course, the fact that it was dead may mean that it was a bit too big.