Stegosaurus

The clam is a benthic, epifaunal and sesile organism with bilateral symmetry. The star is a benthic, epifaunal and sesile organism with pentameral symmetry. The crab is a benthic, epifaunal and vagrant organism with bilateral symmetry. The sea urchin is a benthic, epifaunal and sessile organism with radial symmetry. The hermit crab is a benthic, epifaunal and vagrant organism with bilateral symmetry. The squid is a pelagic and nektonic organism with bilateral symmetry. The barnacles are benthic, epifaunal and sessile organisms.
The crayfish is a benthic, epifaunal and vagrant organism with bilateral symmetry. The shrimp is a benthic, epifaunal and vagrant organism with bilateral symmetry. The turtle is a pelagic and nektonic organism with bilateral symmetry. The bryozoan is a benthic, epifaunal and sessile organism with asymmetric symmetry. The ammonite is a benthic, epifaunal and vagrant organism with bilateral symmetry. The horn coral is a benthic, epifaunal and sessile organism that has radial symmetry. The fish is a pelagic and nektonic organism with bilateral symmetry.
The sea urchin is a benthic, epifaunal and sessile organism that has radial symmetry. The shark is a pelagic and nektonic organism with bilateral symmetry. The ammonite is a benthic, epifaunal and sessile organism with radial symmetry. The trilobite is a benthic, infaunal and vagrant organism with bilateral symmetry. No, it would not be successfull on the sea floor and it certainly would not be successfull burrowing or living in the sea floor, although squid do sometimes prey on benthic organisms. The squid uses its tentacles to grab and eat its prey.

The squid uses its muscles to pump through the water. And has adapted to see better with large eyes. No they would not do so well living on land, they float through the sea so they would not have any means or mobilization, also, they use long tentacles to sting and catch their prey, this would not be very efficient on land. The hermit crab uses the shell to protect itself from prey. Because the animal moves so slowly, it needs the added protection. It could be that the animal could not move fast and would need to curl up in its shell to protect itself from prey.