Aspidochelone

The Aspidochelone is not explicitly stated to have a mythological origin, but it may be related to the symbolism of Satan in medieval bestiaries.

The entity appears as an enormous sea creature, often mistaken for a rocky island due to its massive size. It has huge spines on the ridge of its back and can take various forms, including a whale or vast sea turtle.

The Aspidochelone lures unwary sailors onto its shell with its 'island' appearance, only to pull them underwater and drown them along with their ships and crew. It also emits a sweet smell that attracts fish into its trap, which it then devours.