Spark Double [War of the Spark] Beta Edition players can't untap more than

players can't untap more than two permanents during their untap steps

Siamese twins

sacrifice Mana Vortex

Set: Ultimate Masters Box Topper Type: Instant — Arcane Rarity: Mythic Cost: {4}{R} You may put a creature card from your hand onto the battlefield

Spark Double [War of the Spark] Beta Edition players can't untap more thanSet: War of the Spark Type: Creature Illusion Rarity: Rare Cost: {3}{U} You may have Spark Double enter the battlefield as a copy of a creature or planeswalker you control, except it enters with an additional +1 +1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary if that permanent is legendary.