Well, sort of. Paleontologists have identified a 430 million-year-old fossil of a multi-tentacled sea creature as a new species and dubbed it Sollasina cthulhu after HP Lovecraft's Great Old One. From Yale University:
The new cthulhu, Sollasina, had 45 tentacle-like tube feet, which it used to crawl along the ocean floor and capture food. The creature was small, about the size of a large spider. It was found in the Herefordshire Lagerstätte in the United Kingdom, a site that has proven to be a trove of fossilized ancient sea animals.
"In this paper, we report a new echinoderm — the group that includes sea urchins, sea cucumbers, and sea stars — with soft-tissue preservation," said Yale paleontologist Derek Briggs, a co-author of the study. "This new species belongs to an extinct group called the ophiocistioids. With the aid of high-resolution physical-optical tomography, we describe the species in 3D, revealing internal elements of the water vascular system that were previously unknown in this group and, indeed, in nearly all fossil echinoderms."