Choose one at random —
• You get an emblem with "At the beginning of your upkeep, pay {U}{B}{R}. If you don't, you lose the game."
• Each player discards their hand.
• Planeswalk to Pools of Becoming. (Once there, you can roll the planar die only if you're playing Planechase.)
• For each opponent, exile cards from the top of their library until you exile a nonland card. You may cast those cards without paying their mana costs.
• Destroy all creatures and non-Bolas planeswalkers.
• You get an emblem with "You can cast nonland cards from your sideboard."