Flash vs Mr. Fantastic
Here are the rules. It's in the DC universe so flash has all of his powers. 2 men enter an enclosed room only one man can leave. This is a fight to the death. Everyone knows what the flash can do. Reed is basically, an intelligent plastic man, who is paranoid, can think faster than everyone--byproduct of his powers--and can control his density. He can make him self as hard as a normal human and as tangible as water. Suit is made of unstable molecules--so if flash vibrates thru it will destroy them both--I think. Because bad things happen when you destabilize unstable molecules.