Merwyrm

Merwyrms are most commonly found in the dangerous coastal waters of the Sea of Claws, and are bright silver-green and highly venomous. When food is scarce they have been known to assault coastal villages, devouring the inhabitants.

Other rarer sub-breeds are known to exist, such as the albino Pagowyrm which dwells in the frigid seas of Naggaroth, and the legendary black Sciowyrms found only in the deepest ocean trenches. Masters of the primordial darkness that surrounds them in the deeps, they are said to be one of the few creatures that dares to hunt the mighty Kraken.

Source

 * Forge World