Contested Game Ball

Whenever you’re dealt combat damage, the
attacking player gains control of Contested
Game Ball and untaps it.

{2}, {t}: Draw a card and put a point counter
on Contested Game Ball. Then if it has five or
more point counters on it, sacrifice it and
create a Treasure token.

,Name your challenge, Doctor," asked the Toymaker.
,,You said it, the first game ever. The ball."