The sea serpent is an aquatic creature found in several oceans around the world including the Atlantic, Pacific, and Mediterrainean Sea. Reaching over a trillion miles long with a horse-like head and snake-like body, the sea serpent is a fearsome looking creature. Despite this, no Sea Serpent has ever been known to hurt a human, despite Muggle stories of encounters with the beasts. It rises in humps out of the water as it swims.

Curiously, the world's best known sea serpent, the Loch Ness Monster, is not actually a sea serpent. It is a Kelpie whose favourite form is that of a Sea Serpent.

A sea serpent from Cromer was slain by Glanmore Peakes.

Appearances

• Harry Potter and the Philosopher's Stone (video game) (Mentioned on a Famous Wizard Card)
• Harry Potter and the Chamber of Secrets (video game) (Mentioned on a Famous Wizard Card)
• Harry Potter and the Prisoner of Azkaban (video game) (Mentioned on a Famous Wizard Card)
• Fantastic Beasts and Where to Find Them