Hellboy, a.k.a. Anung Un Rama, is a fictional character created by Mike Mignola for his dark fantasy comic book series of the same name, which debuted in 1994 and was published by Dark Horse Comics.
In the series, Hellboy is a cambion (i.e. half human, half-demon hybrid) brought to Earth as a child by a gateway opened in 1944 by the mad monk Grigori Rasputin, and adopted by Prof. Trevor Bruttenholm of the Bureau for Paranormal Research and Defense. As an adult, Hellboy works as one of the Bureau's agents, defending mankind from supernatural threats, including some which are Lovecraftian in nature. These range from apocalyptic cosmic entities like the Ogdru Jahad, to humans transformed into Frog Monsters. His allies include Abe Sapien, an ichthyoid humanoid; and Johann Kraus, an ectoplasmic spirit in a containment suit. His adventures also regularly involve witches, vampires, fairies, and other folkloric elements.
A live action movie adaptation was released in 2004, followed by a sequel, Hellboy II: The Golden Army, in 2008. Both films were written and directed by Guillermo del Toro and feature creature designs by Wayne Barlowe. Hellboy was played by Ron Perlman, who would later voice a shoggoth in the animated film Howard Lovecraft and the Frozen Kingdom.
The Hellboy movies feature a number of references to the Cthulhu Mythos. The first film opens up with a quote from Des [sic] Vermis Mysteriis, while The Golden Army mentions Bethmoora (a creation of Lord Dunsany, incorporated into the Mythos by H. P. Lovecraft) and features a pair of Elder Things in a brief background appearance, most likely as an Easter egg reference to del Toro's unmade adaptation of At the Mountains of Madness.
In the 2024 film Hellboy: The Crooked Man, Hellboy speculates that the supernatural occurrences in the Appalachian Mountains might be due to a dimensional rift, which he describes as a "Lovecraft type scenario".