Cephalopod Mimicry – The ability to take on the form and/or characteristics of a cephalopod. Cephalopods include octopi and squids.
The Thing (Marvel) has to deal with a one-shot cephalopod from the Negative Zone in Secret Invasion – Fantastic Four #2.
A one-shot cephalopod in Anno Dracula #1 (Titan).
A one-shot armored cephalopod in Fantomex MAX #2.
A one-shot cephalopod in Superman V4 #21.
Undersea Agent (Tower) featured a different octopus every other issue (Undersea Agent #2, #3, #5).
The D&D universe has several ferocious octopi including the Blood Kraken (Creature Collection I), Blood Sea Mutant (Creature Collection II. Dark Menagerie), Sea Kraken (D&D 4th Edition – Monster Manual 3)and the Jungle Squid (Creature Collection III. Savage Bestiary).
The House of Mystery V1 #133, features a giant octopus.
Squidward Tentacles is a sardonic squid in SpongeBob SquarePants.
Giant Squid – TSR 2140A Monstrous Manual
Golden Ammonite – TSR 2173 Monstrous Compendium Annual Volume 4
Morkoth – TSR 2140A Monstrous Manual
Octo Jelly – TSR 2173 Monstrous Compendium Annual Volume 4
Sea Demon – TSR 2173 Monstrous Compendium Annual Volume 4
Tako – TSR 2140A Monstrous Manual