Krakenite

The Krakenites were a species that Professor Hamilton Smith had theories on.

Krakenites were swamp-living aliens with a cylindrical body covered in a thick, grey shell with the texture of barnacle. They had approximately ten tentacles that protruded from the top of the shell.

When Sam Jones went missing in the 23rd century, the Eighth Doctor lodged a missing person report with the Krakenite authorities. (PROSE: Dreamstone Moon)