The single most powerful super power would be...

Making anybody anywhere orgasm on command perpetually.

Thanos wants to snap? Good luck snapping with a big ol clam in his tunic.

Bane is about to go fist to fist with you? Probably too embarrassed with his drawers becoming even heavier.

Dolores Umbridge is about to take down Fred and George's firework display? Can't cast a spell if all she can say is "Oh golly."

You with any super power against me, "Ajax, King of the Climax." You lose that battle like a shoe over an ant. You lose that battle 10/10 times with a stain in your pants.