Petra Sphinx [Legends] Mirrodin Besieged In the reflection

In the reflection

{T}: Double the amount of each type of unspent mana you have

"I'll have my revenge if I have to call on every force from above and below

A living invention born of a grand design

Petra Sphinx [Legends] Mirrodin Besieged In the reflectionSet: Legends Type: Creature Sphinx Rare Cost: {2}{W}{W}{W} {T}: Target player chooses a card name, then reveals the top card of their library. If that card has the chosen name, that player puts it into their hand. If it doesn't, the player puts it into their graveyard. What walks on four legs in the morning, two legs in the afternoon, and three legs in the evening?