I'm not sure if it is because of cultural influence or just the influence of a competitor but Solomon Grundy is very similar to the Hulk.
So similar that I had a harder than normal time trying to find differences to exploit for this battle. Note that as always I am
using the most recent version of the character that I have seen. I haven't seen Grundy in a while but Hulk made an appearance in the Avengers (one of my monthly comics) and he was back to his old angry Hulk version.
The only differences I could think of were that Grundy is a walking dead man composed of plant matter and Hulk is a living creature that reverts back to normal when he calms down.
I will assume that they have equal strength and intelligence. Their tactics will decimate the arena so nothing is left for them to use. They would just keep beating on each other forever. The only
things I see making any difference is the fact that since Grundy is dead he doesn't breathe, but that isn't true since we see him breathing and being knocked out by gas. The other is the Hulk's
famous rage watch amplifies his strength when he gets angrier. I guess there is a possibility that he could become stronger than Grundy and defeat him. This an uneasy desicion. Consider this battle as a lure for anyone who knows better to respond.