Q. We find a fat, ugly, brownish-yellowish fish in the crab pots we set off our dock. It has a big mouth, big eyes and a wide head. Its body tapers off from its mid-section down to its tail. It doesn't look very friendly. Any idea what it is?

A. You've just described an oyster toadfish (Opsanus tau), sometimes called oyster toad or oyster cracker. This fish has strong teeth and powerful jaws -- capable of crushing hard-shelled mollusks -- and a face only its mother could love. Its only attractive feature is its large, luminous blue eyes.

One of the oyster toad's favorite hangouts is crab pots, but it's not picky. Discarded cans, jars, tires, structural debris, rocks, reefs, oyster reefs -- almost any fixed object will do. It can also change color to blend with its surroundings.

Unlike most fish, the oyster toad has no scales. Instead, it's covered in thick mucous, and sometimes warts. Its mouth is filled with blunt teeth. Thick, fleshy, skin flaps surround its lips and eyes. Two sharp spines on its gill covers are used for defense. Fins under its throat stretch out like fans. If caught, its strong jaws snap viciously, making it difficult to get off a hook. It's edible, but if handled its sharp spines can cause nasty wounds. Out of water, it feels soft and squishy.

The oyster toad is an ambush predator. It lies motionless, waiting for prey to wander by, then attacks by surprise. It eats almost anything -- worms, shrimp, oysters, amphipods, crabs, mollusks, squid and small fish. Its teeth and jaws are formidable weapons when fighting other oyster toads.

These odd-looking fish can be quite vocal. To attract a female during spawning season, the male emits a loud foghorn-like call, which can be heard underwater for great distances. When handled out of water, they make a grunting sound.

Oyster toads are found from Maine to the West Indies. They have no commercial value, and are generally considered a nuisance fish because of their potentially dangerous jaws. However, because of low sensitivity to pollution and an ability to live out of the water for extended periods, they are considered an important animal for marine research.

Sherry White works for the N.C. Aquariums public affairs office.