Petra Sphinx [Legends] Magic 2015 but how do we get

but how do we get down

Set: Urza's Saga Type: Artifact Rarity: Uncommon Cost: {1} {1}

you may pay {0} rather than pay this spell's mana cost

you gain 3 life and you may return up to one target creature card from your graveyard to your hand

Set: Pro Tour Promos Type: Creature — Avatar Rarity: Rare Cost: {6}{B}{B} If there are ten or more creature cards total in all graveyards

Petra Sphinx [Legends] Magic 2015 but how do we getSet: 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?