Ralen, Arena Gambler

At the beginning of each opponents upkeep, that player must choose land or nonland card. That
player then reveals the top card of their library. If
the player chooses correctly they draw that card.
If the player chooses incorrectly, place that card
at the bottom of their library and their opponents
gain 2 life.
{g}{w}{u}: Target player gains control of Ralen,
Arena Gambler. Any player may activate this
ability.