Let's go to the Casino!

-Shroud-
At the beginning of each players upkeep, anyone
may bet at least 1 life that the top card of their
library has the highest mana cost. Then each
player reveals the top card of their library. If
your card is the highest cost you gain the
amount of life bet & that many Gold tokens, if
it's not the highest lose the amount of life bet
and target land you control doesn't untap until
next turn.
"You don't have to bet, but you must play"—