Afanc
The Afanc, Avanc, or Addanc is a Welsh lake monster. Unlike its better-known Scottish brethren Nessie, who is generally described as a plesiosaur-like creature, and definitely inhabits only one lake, the Afanc has been described varously as resembling a crocodile, a beaver, or a dwarf, and there are at least five different lakes and one river in which it is said to live.
Dungeons & Dragons
There are two creatures named after this monster in D&D, one spelled Afanc and one spelled Avanc.
Afanc
Afancs are fifty-foot long predatory fish that creates whirlpools big enough to sink ships by swimming in circles rapidly.
Avanc
The Avanc is a twenty-foot long, six-legged crocodile that inhabits Lake Kronov in the Ravenloft domain of Tepest. It is believed to be a humanoid who was polymorphed by the Shadow Fey Prince Loht for some transgression.