Protean Hydra [Magic 2010] Spirit Bear You can only use 1

You can only use 1 "Impcantation Bookstone" effect per turn

Set: Aether Revolt Prerelease Promos Type: Legendary Creature — Human Wizard Rarity: Rare Cost: {1}{U} Instant and sorcery spells you cast cost {1} less to cast

while it has an Xyz Material attached that was originally Dragon-Type

except "Rokket Tracer"

Set: EX: Sandstorm Type: Fire Rarity: Common Retreat cost: Colorless

Protean Hydra [Magic 2010] Spirit Bear You can only use 1Set: Magic 2010 Type: Creature Hydra Rarity: Mythic Cost: {X}{G} Protean Hydra enters the battlefield with X +1 +1 counters on it. If damage would be dealt to Protean Hydra, prevent that damage and remove that many +1 +1 counters from it. Whenever a +1 +1 counter is removed from Protean Hydra, put two +1 +1 counters on it at the beginning of the next end step.