Gtuhanai (The Destroyer God of the Aartnna) is a destructive entity manifesting as a ravenous field of unknown force, which builds itself a body by drawing any metallic elements into it, shredding them, and ultimately becoming a highly destructive vortex of spinning metal fragments. It is unknown whether it is sentient; it does not interact in any meaningful way with human beings. Similar to Hastur, it is a half-brother of Cthulhu and is also related to the slug-like Gla'aki. (This was an injoke from Gtuhanai's creator, J.B. Lee, who was inspired by the work of Lovecraft and Ramsey Campbell, creators of Cthulhu and Gla'aki respectively.) It originated somewhere in the Pleiades stellar region and brings destruction where ever it is summoned.
Behind the Mythos
Gtuhanai was introduced in the story Forces of Change by J.B. Lee, originally published in 1999 in the webzine NetherReal. The story may now be read at FictionPress.com.