- On those occasions when the Hulk gets seriously angry and destructive and unable to differentiate between friend and foe, it can get a little unsettling. And on the flip side, stories where someone is actually able to beat the crap out of the Hulk himself is a frightening visual when you consider his power level. Then you have the cases where someone's trying to take down an especially powerful Hulk, as in World War Hulk and Immortal Hulk, and part of the horror is how far they're willing to go in order to do so.
- One of Mister Hyde's creepiest appearances was in The Incredible Hulk #368, where he cornered Bruce Banner on a train, stabbed him, slammed him into a wall, and taunted him over their Jekyll and Hyde duality, explaining that he decided to kill the Hulk to prove he's superior, as there's no room for two Edward Hydes. Hyde eventually declares he's won, as while the Hulk cares for others, Hyde has no such weakness, and laughs as he falls off the train and down a cliff. The whole thing is made worse by the comic's use of shadows, giving the train scenes an eerie, nightmarish feel. Even Bruce admits that Hyde knew how to push his buttons.
- Issue #377. Doc Samson hypnotizes Bruce to try and reconcile the Hulk and Joe Fixit, as their war for control is turning Bruce into a wreck. While inside Bruce's head they find that he is haunted by a horrifying monster (the "Guilt Hulk") that effortlessly defeats both the Hulk and Joe. We see the monster beating young Bruce on Christmas morning and murdering Bruce's mother, and it's made clear that the monster is Brian Banner.
- Hulk: The End: Bruce Banner is the last living human after two nuclear wars which wiped out everybody else on the planet. When the story picks up Banner has spent years (possibly decades) wandering the radioactive wastelands, completely alone except for an alien recorder bot and the Hulk berating and raging at him inside his head. During that time Bruce has aged into an extremely old and frail man who thinks he may be over 200 years old (and looks every day of it). He wants desperately to die, but the Hulk refuses to let that happen. Bruce even tries to kill himself by jumping off a cliff but it's the Hulk who lands. At one point Bruce is chased by a swarm of giant evolved cockroaches, which are too much even for the Hulk to handle all at once; they overwhelm him and eat most of his flesh and internal organs, including both eyes and his tongue, which Hulk of course regenerates (and this is said to happen regularly). Bruce later has a heart attack and pleads with the Hulk to let them both go, but Hulk refuses and transforms as Bruce is on the point of death. The end of the story leaves the Hulk's fate in doubt but one awful possibility that suggests itself that Bruce is buried deep within the Hulk's psyche and that if the Hulk chooses not to change back, that they are both still stuck together on the dead Earth. Forever. The only difference being that Hulk can't hear Bruce inside his head anymore and as far as he knows, "Hulk is... only one... there is. Hulk feels... cold."
- The Maestro. As mentioned above, Hulk can be as terrifying as you'd expect from one of the most powerful beings on Earth who just so happens to suffer from mental instability and "breath-taking anger management issues". Now, take the Hulk, remove all his positive qualities, and turn all his negative qualities Up to Eleven, and what do you have? The Maestro. Also from above, the sheer scale of the atrocities the Maestro is responsible for, and the depth of his depravity. It's truly terrifying to think that one of the most tragic and pitiable protagonists in fiction could become so utterly broken that he comes out the other side as such an absolute monster.
- Post-Onslaught, the Hulk, literally half the monster he used to be due to being separated from Banner again, starts giving off an unusual and deadly amount of radiation. He was also brain-damaged during this time, and given his usual temperaments, this was a recipe for disaster. One attempt from the army to contain him had him melt the lead containment shield designed to capture him, and the Hulk tearing half his face off. A soldier in a special radiation-resistant suit felt nauseated seeing that and attempted to take his helmet off to throw up, but himself received a horrifying death where his eyes melted as his skin burned from the radiation the Hulk gave off.
- The villain Mercy is essentially the personification of Driven to Suicide, believing that she is doing despairing people a favor by killing them or leading others to kill them. Her powers include energy manipulation, strength, teleportation, flight, shapeshifting, and telepathy, and she can suppress consciousnesses to make it easier for people to die.
- The Immortal Hulk takes the story into the dark side of the Hulk, featuring Banner not just grappling with his dark side but the Hulk going on a trip to Hell itself.
Nightmare Fuel / Incredible Hulk