Probably Man-Thing but I don't know how just yet. Not sure Groot can physically harm him.
ANN
AnnabethSenior Member
Man-Thing is too powerful he is at least as mighty as Swamp Thing
HOR
Horus1Pantheon Caretaker
At first glance I would go Man-Thing, but Groot is fireproof. I guess Man-Thing could BFR him, so he wins that way. A straight up slugfest wouldn't favor either, as they are both really durable.
HEN
Henry_PymUltron Bound
Man-Thing's acid has burned Hulk.
HOR
Horus1Pantheon Caretaker
Originally posted by Henry_Pym Man-Thing's acid has burned Hulk.