|“||How I've missed your people's spirit.||„|
|~ Ichthultu to Hawkgirl about Thanagarians who no longer worship him.|
|“||We don't miss you. We outgrew you, thousands of years ago.||„|
|~ Hawkgirl to Ichthultu about her people's millienia-old rejection of him.|
Ichthultu (also known as Icthultu and Great Ichthultu) was a bloodthirsty god-like beast and a powerful member of an ancient race of extradimensional monsters known as the Old Ones. He is an enemy of the Justice League and the primary antagonist of the Justice League episode "The Terror Beyond".
Ichthultu's appearance is that of a giant green squid with large bright yellow eyes and serpentine tentacles that has eyes attached to them.
Eons ago, Ichthultu and the Old Ones terrorized the universe. Each planet they conquered, they convinced or forced the native inhabitants to worship them. Apparently, Ichthultu was once worshipped by the Thanagarians until they rejected him, as well as religion outright, having grown tired of his constant demands for sacrifice. Soon, Ichthultu set his eyes towards Earth, starting with Atlantis. King Poseidon used all of Earth's mystical energy to forge a trident to banish the Old Ones from Earth.
Thousands of year later, Ichthultu prepared for his return. Doctor Fate, Aquaman, and Solomon Grundy began a ritual to hinder his efforts. But the Justice League's interference disrupted the ceremony, allowing Ichthultu to temporarily materialize. Doctor Fate and Hawkgirl managed to seal the rift, preventing Icthultu from coming to Earth. With little choice, the Justice League went to Icthultu's home dimension known as Relex to stop him.
Ichthultu was apparently destroyed by the joint efforts of Hawkgirl and Solomon Grundy by destroying his brain while his fellow Old Ones forcibly retreated back to their homeworld. Even if Ichthultu survived, he was likely left powerless and brain-dead for eternity. Solomon Grundy did not survive the battle but before he died, he and Hawkgirl became friends.
- Ichthultu's name, appearance, and title as an "Old One" is based on H.P. Lovecraft's character Cthulhu.
- Ichthultu was voiced by heavy metal musician/director Rob Zombie.