Aquaman actually fought Cthulhu in DC Comics!
Once, in The Brave and the Bold #32 (2010), Aquaman teams up with the Demon to journey to an underwater city, fight fishmen, and stop the horrible menace of Cth. . . wait, is that still under copyright? Some idiots claim they own it but have no papers to prove it? It's actually in the public domain now? Nevermind, we'll call it, um, a Night God. That's great! Let's go to print!
Then, in Aquaman Vol 7 #23 (2013).
Oh, but wait, that's Aquaman's buddy, Topo, from Prime Earth. Topo is a sentient octopus that first appeared in Adventure Comics #229 (1956). Wanna see what he used to look like?
ALL THE MEMES