Fossilized Giant Mudcrab is an unmarked location found in The Elder Scrolls V: Skyrim. This small pond is located between Broken Fang Cave and Gjukar's Monument. It contains a giant fossilized mudcrab, as well as several normal-sized living mudcrabs.
Next to the pond is a small den that contains a searchable skeleton, as well as a sword and shield.
During the quest "Kyne's Sacred Trials," the Dragonborn is asked to kill the Guardian Mudcrab. The Guardian Mudcrab is far larger than a normal Mudcrab and it will spawn at this location, suggesting that it is the spirit of the fossilized giant mudcrab.