Petra Sphinx [Legends] 143a with a Level from 4

with a Level from 4 to 8

As Hallowed Fountain enters the battlefield

you can Special Summon 1 Fiend-Type monster from your hand or from either player's Graveyard

If X is 4 or more

You may spend blue mana as though it were mana of any color to pay the activation costs of Quicksilver Elemental's abilities

Petra Sphinx [Legends] 143a with a Level from 4Set: Legends Type: Creature Sphinx Rarity: 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?