The Grebnedu resembles a large snake-like creature with a large head, massive fins, a long split-jaw, with a sharp beak above. Below the Grebnedu's small black eyes are, two fish-like barbels (possibly bioluminescent lures) hanging down its face. The snake-like body of the Grebnedu is smooth with spines down its back. The long lower jaw folds up into the Grebnedu’s throat.