Most large squid grip prey with suckers reinforced by rings of chitinous teeth. Mesonychoteuthis adds hooks. Two rows of them sit on the club at the end of each tentacle, mounted on short stalks in shallow depressions so they can rotate; the hooks along the eight arms are fixed. Whether the squid turns them actively, or they swivel passively once a hook has caught, is not known. The scars they leave on sperm whales are distinguishable from the circular ring marks a giant squid makes.
Size is the more commonly discussed feature. The best-documented specimen, landed by a New Zealand vessel in 2007 and now held at Te Papa Tongarewa in Wellington, weighed roughly 495 kilograms, the heaviest cephalopod ever weighed. Mantle length is the meaningful measure here: colossal squid have shorter tentacles than giant squid despite greater mass.
A persistent misreport treats colossal and giant squid as the same animal. They are separate species in different families, and the colossal squid is essentially confined to the Southern Ocean. Much of what is known about its diet comes indirectly from beaks in sperm whale and sleeper shark stomachs.