Spider-man thinks he can defeat the Hulk, but would need to kill the latter to do so.
Peter Parker confesses to Mary Jane that everyone in the super hero community studies one another whenever they team up, so that in the possible event that someone gets mind-controlled or possessed, they’d have a way to defeat one another. I know for certain that Cyclops does this to everyone, especially members of the X-men.
Kinda reminds me of Batman studying the Justice League and creating failsafes or counter measures against them. I