[A burst of laughter, easily mistaken for genuine amusement.]

No deal. Currency doesn’t seem so useful round these parts...but I have an alternative. [They raise a single finger, staring him dead in the—eyelights.] The loser shall owe the victor one favour. Just the one.

Of course, said favour cannot require the loser to come to harm, or to harm another. I think that’s a fair stipulation, don’t you?