Perhaps it was when Hellboy (David Harbour) chased a pig baby changeling in a diaper up a chimney that it fully hit me. I couldn’t help but wonder: What on earth am I watching?

With this latest reboot of the gothic fantasy character “Hellboy,” director Neil Marshall unleashes his bloodthirsty zest for grime and gore. It’s certainly… a lot.

Harbour is an ideal choice to sport sawed-off horns as the demon with a heart of gold, an investigator working for his father (Ian McShane) at the Bureau of Paranormal Research and Defense. Harbour has a warmth and humor that shines through all the prosthetics, and an ease with sarcastic wisecracks too.

The snarky asides, which permeate even the solemn voice-over that opens the film (which starts in yes, the 5th century, with yes, King Arthur), let us know everyone here is in on the joke. It’s OK to laugh with the movie, even if it feels like we’re laughing at it.

Describing the plot of this truly crazy monster mash is a fool’s errand. The gist is monster hunter Hellboy has to confront his own origins and existence as half-man, half-monster while battling to save the world from the greatest monster of all, the Blood Queen witch Vivian Nimue (Milla Jovovich), who was dismembered by King Arthur and locked in separate coffins to keep her from running roughshod over the earth.

Within that general framework, writer Andrew Cosby has stuffed a rogue’s gallery of ghoulish characters, subplots and flashbacks. This movie has everything: giants, witches, lucha libre wrestlers, cheetah werewolves, Nazi occult rituals featuring cameos by Rasputin and Leni Riefenstahl, Sasha Lane as a psychic who pukes up slimy spiritual apparitions, a boar-man with a Scottish accent and an iron jockstrap, Winston Churchill’s desk, an amusing appearance from Merlin, mystical secret societies and of course, Baba Yaga.

All this comes straight from the comic, so fans should be pleased at the depth and breadth of the lore in the film. Those who are less familiar with the Hellboy canon might be overwhelmed, as this all hurtles at a relentless, unforgiving pace, glued together with many, many crunchy guitar licks.

“HELLBOY”

**

(R, 2:00)