Spoilers for Hulk #8 by Marvel Comics
In the main Marvel Comics continuity, Thor just took on one of his ultimate forms, as the hero proved to be stronger than the Hulk in a brutal fashion. In Hulk #8 by Marvel Comics, a Hulked-out Thor doesn't hold back against the Jade Giant, resulting in the God of Thunder ripping the arm directly off his powerful opponent in a pure display of dominance against Marvel's usual strongest hero.
In the current Hulk and Thor 'Banner of War' crossover from Marvel Comics, the current King of Asgard has ed the Avengers in searching down the rogue Hulk, who was responsible for an incident that left an entire bar dead. Looking to make him pay for his crimes, Thor and Iron Man confronted their former ally, but after a Gamma-explosion was unleashed, Thor transformed into his own Hulk. In response, the Jade Giant himself picked up Mjolnir and wielded Thor's hammer, as Odin jumped in his psyche to talk and reason with Bruce Banner inside Starship Hulk.
In Hulk #8 by Donny Cates, Daniel Warren Johnson, Martin Coccolo, Matt Wilson and VC's Cory Petit from Marvel Comics, a Hulked-out Thor gives the Hulk everything that he can handle, as he isn't holding back against his opponent. Thor ends up ripping Hulk's arm clean off his body as the Jade Giant screams in pain. Realizing Thor's ultimate form is even more powerful than the Hulk, Odin gets Bruce Banner to try to knock him into the world tree and tie him up with its branches. However, Thor breaks free and lifts the tree from its roots, and smashes it.
As Beta Ray Bill puts it, when the Hulk previously faced the Avenger, his powers weren't fully unleashed. But, by becoming a version of the Hulk, rage that's been held back for hundreds of years finally breaks through, showcasing an ultimate form of Thor that the world has never seen before. This version of Thor didn't show any mercy, and proved what it's really like to fight a Marvel god who is stronger than the Hulk.
By the end of the issue, Thor and Hulk both return to their usual forms as the Jade Giant jumps off into space. However, during the 'Banner of War' crossover event, Thor proved that with the Hulk's rage and his own powers as a god, his ultimate form in the current Marvel continuity is nearly unstoppable. Thor proved to be stronger than the Hulk during their epic battle, as his new powers nearly led to the green monster's demise.
