Mana Short [Limited Edition Beta] Cat Warrior Set: Lorwyn Type: Artifact Rarity:

Set: Lorwyn Type: Artifact Rarity: Rare Cost: {3} You may activate abilities of creatures you control as though those creatures had haste

the player can activate mana abilities only if they're from lands that player controls and only if mana they produce is spent to activate other mana abilities of lands the player controls and/or to play that card

At the academy

And still you will not have suffered enough

Mana Short [Limited Edition Beta] Cat Warrior Set: Lorwyn Type: Artifact Rarity:Set: Limited Edition Beta Type: Instant Rarity: Rare Cost: {2}{U} Tap all lands target player controls and that player loses all unspent mana.