Outfit Dwayne Johnson, the hulking former WWE star, in a pair of cargo pants and a snug Henley T-shirt and throw him into any extreme situation — jungle-based video game, diesel-fueled car stunts, beach crimes, fighting an earthquake — and it works.

So pairing Johnson with a giant albino gorilla in the video game adaptation “Rampage” feels right.

The tagline reads “big meets bigger,” and that’s about all you need to know. Johnson, who usually dwarfs his co-stars, this time gets to feel small. It’s big all right — big, dumb fun.

“Rampage” expands the narrative of the retro game, which involved a giant gorilla, wolf and crocodile crunching skyscrapers into dust.

In this iteration the writers have anthropomorphized the gorilla, who is named George and is the best friend of Davis Okoye (Johnson), a primatologist with a background in the Army Special Forces and anti-poaching activism, naturally.

When a spacecraft carrying research samples from a shady corporate gene-editing experiment explodes in the atmosphere, scattering its tainted shrapnel across the U.S., George, a wolf and a crocodile are infected with the stuff. It causes them to grow to an enormous size, act out aggressively and take on the genetic qualities of other animals, like rapid cell regeneration, or exploding porcupine quills, or, you know, flying.

Hoping to save his friend, Davis links up with a disgraced genetic scientist, Kate (Naomie Harris), and barges right into the middle of the operation to take down these monsters that are threatening to level Chicago, Godzilla-style.

This is a B-movie monster flick starring quite possibly the biggest movie star (or at least the most profitable) in the world, and “Rampage” knows exactly what it is. It doesn’t try to be anything other than that. It has a decidedly 1990s feel, self-aware, quippy, loaded with archetypes.

The script smashes through rapid-fire character introductions, each bigger and broader than the last. Malin Akerman and Jake Lacy are a pair of hilarious villains.

But it’s Jeffrey Dean Morgan who does as much structural damage as the monsters do, chewing the scenery as a swaggering cowboy of a government agent. But he too is upstaged by the SuperCroc, who makes possibly the most memorable entrance of the year.

All these characters make for a movie that never slows down, but among all the mayhem, Johnson is lost. He doesn’t get a chance to truly show his comedy chops or acting skill, and his character is the least developed. He is, in fact, dwarfed by George, and every other hammy performance on screen, his presence shockingly overshadowed, his usually radioactive charisma dimmed. As a stupefyingly silly throwback monster movie, “Rampage” romps, but as a Johnson vehicle, sadly, it flops.