In Marvel lore, Hulk. However, this effect isn't limited to humans, and there are several gamma monstrosities that were originally completely different forms of life. In this list, we're looking at the aliens, robots and animals that became terrifying Hulks.

Here are the 12 strongest non-human Hulks seen so far in Hulk lore. While all Hulks are monsters in one way or another, these characters were never human, often making them stronger or more vicious than even Hulk's most despicable enemies.

12 The Dogs of War, aka Gamma Dogs

Debuted in Incredible Hulk Volume 2 #14 by Paul Jenkins and Ron Garney

There have been various gamma dogs over Hulk history, including the Cujo-esque Sirius, who became a monster after Bruce Banner tried to heal a family pet using gamma radiation. However, the deadliest version of gamma hounds came in the Dogs of War - a pack of superstrong, rage-filled dogs created by General John Ryker, who fed a group of trained attack dogs gamma-irradiated meat. The Dogs of War savaged Hulk on Ryker's command, but ultimately the Jade Giant was able to win out and escape.

Gamma Dogs most famously appeared in Ang Lee's Hulk movie, where Hulk's father irradiated the mastiff Smokey, pitbull Sammy and Poodle Lilly.

11 The Outcasts

Introduced in Incredible Hulk #327 by Al Milgrom and Steve Geiger

The Hulk wasn't the only monster created by Bruce Banner's gamma bomb. In 1986, fans learned that the animals and plant-life in the vicinity of the blast were also slowly transformed, becoming a group of monsters known as the Outcasts. The Outcasts were made up of mutated snakes, bats and birds, as well as desert flora given humanoid form, living peacefully in underground tunnels left behind by Bruce Banner. While these animals briefly became Hulk's allies, they rejected him after coming to believe that his notoriety would lead to their discovery by humanity.

10 Gamma Insects

First Seen in Planet Hulk #1 by Sam Humphries and Marc Laming

Named for the iconic storyline where Hulk takes over the planet Sakaar, 2015's Planet Hulk takes place in a world that has been totally irradiated by gamma energy. All the planet's fauna and flora are gamma-powered, offering up several entries on this list. The series sees a barbarian version of Captain America and his pet tyrannosaurus Devil try to cross the gamma wastelands, encountering various terrifying non-human Hulks.

One of the most disturbing monsters Cap encounters are the gamma insects - subterranean monsters that burst through the ground and consume any travelers who dare to cross their desert territory. The Captain and Devil are almost eaten alive by the insects, which - while not individually that powerful (for a Hulk) - are near-unbeatable in great numbers. Thankfully, they're saved by the scientist Doc Green, who uses a custom device to drive the insects away.

9 Monolith's Horse

From Hulk Volume 6 #9 by Donny Cates and Ryan Ottley

After Hulk redirected a gamma blast to another reality, an entire planet of people, animals and plants were turned into gamma monsters. This new 'Hulk Planet' (not to be confused with 'Planet Hulk') was ruled over by the powerful superhuman Monolith, inhabited by a population of Hulks who worshiped the original as a god. While these beings are a little close to humans to appear on this list, one Hulk Planet resident who does deserve a place is Monolith's gigantic gamma horse.

This imposing stallion was incredibly strong, and the species were used to constuct Hulk Planet's massive statues of the Hulk. Able to crash through concrete with little effort, Monolith's horse also had the advantage of its rider's staff, which could create energy platforms, effectively allowing Monolith's steed to run on air, acting more like a rocket than a horse.

8 The Hulk-Eater

First Seen in Planet Hulk #2 by Sam Humphries and Marc Laming

Back on Planet Hulk, Captain America and Devil encounter the Hulk-Eater - a gigantic Venus flytrap that eats Hulks alive. The predatory plant has razor-sharp teeth and a powerful 'tongue' that restrains its targets and drags them towards its terrifying maw. Marc Laming's creator notes in the comic state that the Hulk-Eater was inspired by John Wyndham's iconic horror novel Day of the Triffids, in which predatory plants run amok after a mysterious cosmic event blinds most of humanity.

7 The Boar Brothers and Bruce Banner's Other Gamma Beasts

First Seen in Incredible Hulk Volume 3 #1 by Jason Aaron and Marc Silvestri

In Incredible Hulk Volume 3, Bruce Banner and Hulk are given separate bodies, finally allowing them to be free of each other. Unfortunately, because Hulk is part of Banner's personality, Bruce descends into paranoia and cruelty without him. Bruce sets himself up on an island, experimenting on various animals with gamma and creating an army of superstrong snakes, lizards, monkeys and gigantic gamma-sharks.

Among Bruce's most unique creations were the Boar Brothers - two wild boars granted humanoid bodies and enhanced intelligence by his experiments. Named 26 and 27, the Boar Brothers acted as Bruce's enforcers and helped with his attempts to capture the Hulk to use in his experiments. Hulk engaged in fights with a variety of Bruce's creations, but the Boar Brothers packed the most reliable punch. Thankfully, Bruce was ultimately merged with Hulk once again, restoring his sanity - however, many of his gamma beasts are still out there.

6 Korg the Kronan

Full Debut Incredible Hulk Volume 2 #93 by Greg Pak and Carlo Pagulayan

Korg the Kronan is a rare 'Hulk' in that his strength doesn't come from gamma radiation. A native of the planet Ria, Korg was one of the aliens encountered by Thor during his iconic first appearance in Journey Into Mystery #83 (by Stan Lee, Larry Lieber and Jack Kirby) - or so Incredible Hulk #93 established. Korg became one of the Green Goliath's allies on the planet Sakaar, helping him to defeat the tyrannical Red King. Korg is naturally strong due to his alien physiology and warrior past, and met Hulk during one of Sakaar's brutal gladiatorial contests, becoming one of his Warbound.

Unlike the other Warbound, Korg later became an honorary Hulk after being welcomed into the 'Hulk Family' team, traveling alongside Hulk, his son Skaar, his daughter Lyra and Jennifer Walters' She-Hulk. Korg remains one of Hulk's closest friends and operates as a hero on Earth, despite living with the same distrust and fear directed at other 'Hulks.'

Korg is voiced by Taika Waititi in the MCU, having debuted in 2017's Thor: Ragnarok.

5 Bull Hulks

First Seen in Planet Hulk #2 by Sam Humphries and Marc Laming

Journeying across Planet Hulk, Captain America and Devil encounter a herd of Bull Hulks - gigantic megafauna with deadly horns and tusks. Incredibly strong, individual Bull Hulks are capable of matching Devil Dinosaur's strength, forcing even the human-Hulk Doc Green to flee for his life.

4 Titan

Introduced in Spider-Woman Volume 8 #7 by Steve Foxe and Ig Guara... Kind of

A recent introduction to Marvel lore, Titan was one of several young heroes experimented on by Hydra... or so he claimed. In fact, Titan wasn't a kid who stumbled onto gamma powers, but a mech created by Kondrati Topolov, aka Hulk's old enemy the Gremlin. The Titan mech was strong enough to as a new 'sidekick' to the Hulk, but was ultimately just advanced armor created by the Gremlin so he could keep an eye on the other young superhumans created by his experiments. Thankfully, Spider-Woman exposed Titan's true identity, and the freed superhumans went on to found Marvel's New Champions team.

The Titan mech was incredibly strong, and was advanced enough to as a biological being. The mech could also unleash blasts of electrical energy used to incapacitate the Gremlin's opponents.

3 The Sea Hulk

First Seen in Planet Hulk #2 by Sam Humphries and Marc Laming

The deadliest gamma mutate seen in Planet Hulk, the Sea Hulk is a gigantic aquatic monster inspired by the iconic work of Ray Harryhausen (the animator and special effects creator behind movies like Clash of the Titans and The 7th Voyage of Sinbad.) This Kraken-like gamma monster is an amalgam of aquatic beasts, with artist Marc Laming stating that, "there's a touch of shark there, a bit of octopus there, a dash of humpbacked whale... all thrown into a Hulked-out blender."

The Sea Hulk raises the dark potential of what gamma can do to water-dwelling creatures, which can grow to even larger size in their unique environment. Like the Hulk-Eater, the Sea Hulk is capable of killing and consuming regular human Hulks, though thankfully Devil is able to kill it after a protracted fight.