Avanc

The avanc is an enormous crocodile-like beast fully 20 feet from nose to tail, with six legs, or six fins; trustworthy witnesses say it has legs in the shallows and fins in deep water. Its long, narrow snout resembles a cayman's, and its mottled dark green scales disappear among marsh plants. The small black eyes are as cold as a snake's yet shine with spiteful intelligence. It is greedy and cruel, the terror of fishermen and swimmers on the misty highland lake it haunts.

When it hears travelers along the shore, the avanc slips into reeds or marsh grass at the water's edge and waits without moving a muscle. Even a scout who has said outright that she is watching for an ambush spots it with just 5% odds for each of her experience levels. Once someone comes within 15 feet, it lunges, giving the target -2 on surprise.

Its jaws, lined with dagger teeth, bite for 3d4, and its heavy tail can lash a different foe for 2d10; it can never use both on the same target. Swimmers it simply rises beneath and drags down to drown, one after another. Small boats it wrecks with a whirlpool before hauling the occupants into the depths.

Once a day, while not fighting, the avanc can stir up a whirlpool 100 feet across in a lake, pond or other fresh water. Every vessel caught in it must pass a seaworthiness check each round or overturn, which is mostly how it gets sailors into the water to eat.

Its thick scales give it a superb Armor Class and great resistance to heat and flame. Normal fire has no effect at all, and magical fire such as a fireball does half damage, or a quarter if it makes its saving throw.

No one knows its true beginnings, but it is thought to have been a man, or some other humanoid, who crossed a cruel faerie king and was polymorphed into this gilled, crocodilian shape as punishment.

It speaks the tongues of crocodiles and fish, which usually do what it says even though nothing magical forces them, as well as those of the Unseelie shadow fey. It does not live among crocodiles or fish, though it talks with them when they meet. No mate has ever been seen with it, and in this shape it may not be able to breed at all.

The avanc will cheerfully devour a dozen grown men if it can, but it also survives long spells without food. After a full feast of twelve to fifteen man-sized creatures, it sinks to the lake bottom and sleeps one week for each victim eaten. It rules its lake as top predator and stars in countless stories told by the fisherfolk and children of the shore.