The Elder Gods are a pantheon of malevolent extra-dimensional entities in the IDW Comics universe. The first time an Elder God appeared was in 2012 in the first issue of the 1st volume of Infestation 2, the first chapter in the Infestation 2 event in IDW comics.
The Elder Gods are malevolent entities trapped within their dimensional prison, who are able to influence the minds of sensitive beings in the material universe. One of whom was Howard Phillips Lovecraft, who with his horror prose channeled the call of the Elder Gods. Oblivion a clandestine organization killed him, before his art could summon the Elder Gods to the universe. His stories continued spreading throughout popular culture, and with the help of the Artillica (powerful artifacts combining magic and technology), the collective imagination of humanity let the Elder Gods loose from their prison.
In one reality, the Autobots in 19th century Earth battled an Elder God, the fish people who served it, and Decepticons who had been corrupted by their new god into eldritch transformers. In another reality, a Cobra scientist orchestrated the transformation of Cobra base personnel into humanoid abominations. A cult in the high fantasy world of Eberron summoned one of the Elder Gods to their city. In another world, the heralds and fishmen of the Elder Gods were combated by the agents of the Covert Vampiric Operations. The Teenage Mutant Ninja Turtles were forced to fight a manifestation of Shub-Niggurath.