The sea monster appears to be some type of eurypterid-crab hybrid. Eurypterids, often informally called sea scorpions, are a group of extinct arthropods that form the order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period that inhabited the worlds oceans around 467 million years ago.
Although popularly called "sea scorpions", only the earliest eurypterids were marine; many later forms lived in brackish or fresh water, and they were not true scorpions. Some studies suggest that a dual respiratory system was present, which would have allowed for short periods of time on land in terrestrial environments.
Eurypterids became extinct during the late Devonian period between 25 million to 500,000 years ago.
NOTE : No, it is not a crab... I believe it is a henwey...
