Not sure if this has already been created but,
If you could do something you and others would normally consider "Impossible" or "Almost Impossible"
What would it be?
And it would only be a one-time thing. :'(
Example: Jump off a cliff that's over9000 feet and survive.
Walking through fire unscathed.
Breathing under water.
I'd hack into a//the super computer for the lulz.
Which to me is considered impossible. :'D