Mysterio vs Thor (theres a twist, so please read!)
mysterio has made an amazing discovery! he has created a compound that makes a person unable to figure out mysterio's powers. somehow, sneakily he uses it on thor. seeing as the stuff takes a week to set in, mysterio preps during that time for a battle with thor!
rundown:
thor: completely and totally unable to discover what mysterio's powers are
mysterio: a week of prep
win requirements
thor: putting mysterio down for the count
mysterio: thor tires himself out or gives up (of if you think mysterio can actually think something up that can defeat thor more directly)
im completely aware that if thor hits mysterio its over, the point here is will thor be able to hit mysterio if he is completely unable to figure out what mysterio is doing
__________________ He is Jreko Than, and his power is that of a Raging Inferno.
Maybe the better question is, what can Mysterio do to defeat Thor in any way, shape or form?
So Thor becomes confused that he is fighting in Ragnorok and goes ape-sh!t...Mysterio has no offensive capabilty that can come close to taking Thor out for good.
Sure, he could confuse the hell out of Thor, but as Thor is immortal (or at least longer-lived than Mysterio) Thor outlasts...