"Like an upset moray eel" - I rather like that, a neat bit of imagery.

Here's an extract from a Wikiedia article: "The morays are frequently thought of as particularly vicious or ill-tempered animals. In truth, morays hide from humans in crevices and would rather flee than fight. They are shy and secretive, and attack humans only in self-defence or mistaken identity. Most attacks stem from disruption of a moray's burrow "