The Colossal Squid has eight arms and two tentacles and lives in the deep ocean and is bigger than a giant squid. The Colossal Squid is also sometimes called the Antarctic or Giant Cranch Squid, which is believed to be the largest squid species.  Colossal squid are known to inhabit the abyssal depths of the ocean primarily in the Southern Ocean that circumnavigates Antarctica. The largest carnivore in sea, the sperm whale has provided the evidence of existence of colossal squids, from their stomachs. Marks have been found on the backs of sperm whales made hooks by colossal squids. 

One of the major  morphological differences between the giant squid and the colossal squid is the existence of swiveling hooks on each of the sucker discs in the clubs at the ends of the colossal squid's feeding tentacles. Either way, both of these species of squid make for formidable and terrifying predators of the deep sea. Colossal Squid are a major prey item for Antarctic sperm whales feeding in the Southern Ocean.The total food consumed by sperm whales contains 77% of colossal squids. Colossal squid the largest invertebrates in the world. The most amazing characteristic of colossal squids is that they have the largest eyes of any living on earth - even bigger than the blue whale. Most of the evidence of these colossal squids that is gathered from the stomachs of sperm whales which have inside their stomach the enormous beaks of the colossal squid.