giant squid

Short definition from Wiktionary

Noun

1. 1
   Any of the very large squid, of the genus Architeuthis (family Architeuthidae), that live at great depths, and of which little is known.
2. 2
   Any of other large squid of other families, about which less is known.
3. 3
   Synonym of Kraken (Norse sea monster)
4. 4
   Synonym of Cthulhu (Lovecraftian horror monster)