The sea-dragon appears in some medieval encyclopedias. The sea-dragon has stingers that inject poison into whatever spot it strikes.

Albertus Magnus add two serpents to the genus of sea-dragons: haren, which is dark and has a somewhat hairy head; and carnen, a very large serpent with a bite similar to that of a viper.

A sea-dragon's bones when burned to ash can heal toothaches.

The sea-dragon may be one of the toothed eels, like the moray,