Aligned Hedron Network [Battle for Zendikar Prerelease Promos] Hydra Avatar Centaur Chieftain has "When Centaur

Centaur Chieftain has "When Centaur Chieftain enters the battlefield

Take an extra turn after this one if an opponent cast a blue spell this turn

Assign each pile to a different one of those attacking creatures at random

but at a price that was etched on her fate

target creature gains "{T}: Return target nonland permanent to its owner's hand

Aligned Hedron Network [Battle for Zendikar Prerelease Promos] Hydra Avatar Centaur Chieftain has "When CentaurSet: Battle for Zendikar Prerelease Promos Type: Artifact Rarity: Rare Cost: {4} When Aligned Hedron Network enters the battlefield, exile all creatures with power 5 or greater until Aligned Hedron Network leaves the battlefield. (Those creatures return under their owners' control.) The last hedron slotted into place, locking Ulamog in an infinite loop of binding energy.