Petra Sphinx [Legends] Rivals of Ixalan Prerelease Promos if Clockwork Avian attacked or

if Clockwork Avian attacked or blocked this combat

(A permanent with shroud can't be the target of spells or abilities

Set: Shadowmoor Type: Sorcery Rarity: Rare Cost: {6}{B} Starting with you

Juggernaut can't be blocked by Walls

Set: Tempest Type: Artifact Rarity: Rare Cost: {1} {3}

Petra Sphinx [Legends] Rivals of Ixalan Prerelease Promos if Clockwork Avian attacked orSet: 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?