The Krakenites were a species that Professor Hamilton Smith had theories on.
They were a swamp-dwelling species with cylindrical bodies 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)