Boobrie

Picture a loon grown as big as a person and dyed completely black. Its harsh, booming cry can be heard several miles off.

The boobrie stabs with a 2-foot beak. Once every three rounds it can also rear back and slam a wing into any creature standing directly ahead within 5 feet; the blow hits automatically for 1d6, and the target must pass a Dexterity check or be knocked down and drop whatever it holds. It often waits concealed in reeds at the water's edge and attacks anything up to sheep size that comes close, small children included.

Boobries haunt remote upland lakes across northern and western Europe, notably in western Scotland. Pairs form in spring and build floating nests of vegetation as much as 20 feet across, where the female lays 1d4 eggs. Through late spring and early summer both parents are busy feeding the chicks. Any treasure they own lies in the nest during this season, carried in on human victims.

Fish make up most of the diet, along with any mammal they can catch, especially lambs and calves straying near the shore. Apart from dragons, wyverns and similar monsters, their only real enemies are farmers who hunt them to protect their herds.