Karamthulhu

A Karamthulhu can be obtained by fishing for slugs during the Rum Deal quest. They are also dropped by:
 * Zombie pirates
 * Zombie swabs

Karamthulhus are mentioned in the second Summoning Development Diary where they are said to attack enemies from a fish bowl. Previously, if you tried to use an alchemy spell on it you would get the message, "You cannot cast alchemy on your follower!"

Rocking Out quest
A Karamthulhu is also part of the Rocking Out quest. They are caught in order to obtain a key used during the quest.


 * Using the Catch option: You catch the Karamthulhu and take the key it is holding.
 * Examine: "Lord of the blue abyss."

Trivia

 * Karamthulhu is a portmanteau of Karambwan and Cthulhu, a fictional squid god and character in many of H. P. Lovecraft's stories. Because of this, there are many ways to pronounce the "...thulhu" of Karamthulhu's name, from (Kig-Hoo-Loo) to (KLOO-loo). H.P. Lovecraft himself wrote many of the pronunciations, which seemed to vary from story to story. It wasn't until after his death that the pronunciation (K-THOO-loo) was popularized.
 * If a player dies with a Karamthulhu in their inventory, it will appear as an NPC briefly.
 * A glitch was discovered involving Summoning a Karamthulhu on 12 January 2008, before Summoning's release. The glitch was fixed the same day.  The glitch had apparently been around since the Rum Deal quest was released.  This had been mentioned on a Summoning Development Diary that they knew this glitch was in the game, but not many players had found it, or paid any attention to it.