10 million USD, but you have to slug a random human being in the face.

Once you agree, a random person from anywhere in the world appears in front of you. You have 5 seconds to slug them as hard as you can. Afterward, they are transported back to wherever they just were previously, injuries and all. The 10 million USD is then deposited into your bank account, tax-free.

This could be anyone in the world at any time. It could be Donald Trump, a child going through chemo; anyone currently alive and not in a coma /brain-dead. If you agree but then back out after the random person is generated, prime Mike Tyson will appear and sock you in the face instead (he will be wearing boxing gloves).

EDIT: To clarify, no, you don't get any money if you back out after agreeing to do it. You get punched by Mike Tyson.

Do you accept?