Alien or animal?

They are Horseshoe crabs which are considered living fossils.
Their blood is blue because of copper.

Where can you find these amazing creatures?
The Japanese horseshoe crab is found in the Seto Inland Sea.

The Atlantic horseshoe crab is found in the Gulf of Mexico and along the northern Atlantic coast of North America. One main area is Delaware Bay, although stray individuals are occasionally found in Europe.

Horseshoe crabs can also be found along the east coast of India.