In 1988 Marvel Comics pitted The Thing against The Hulk, first in Fantastic Four #320 and continued in The Incredible Hulk #350.
Fantastic Four #320
A grey-looking Hulk with the power to reason gets tricked (ironically) by Dr. Doom to attack The Thing, whose power has “multiplied substantially” and is the leader of the Fantastic Four at the time. The original Hulk is assumed to be dead and the grey Hulk believes he’s the original.
The Hulk ambushes The Thing and they go to war. After some back and forth, Thing gets the upper hand until the original Hulk appears.
The Incredible Hulk #350
The Thing gets to have a round 2 fight, this time with the green Hulk. And while that’s happening, the scene switches to Dr. Doom and the grey Hulk conversing. Doom explains that The Hulk who The Thing is fighting is a robot. The Thing even suspects this could be the case and confirms his suspicion as the Hulk breaks into metal fragments.
But then the grey Hulk re-appears, this time with a plan to outsmart The Thing, not out-muscle him. And outsmart him he does, getting The Thing to run around for an hour trying to chase him until The Thing gets knocked out.