Knowledge Vault

four generic mana Artifact

two generic mana , tap this permanent : Exile the top card of your library face down.

zero mana : Sacrifice this artifact. If you do, discard your hand, then put all cards exiled with this artifact into their owner's hand.

When this artifact leaves the battlefield, put all cards exiled with it into their owner's graveyard.

Showing Legends#281

Price

41.78 $

3 printings

Daily estimate from Scryfall, not a shop quote.

2009-10-01
You don't get to look at the cards exiled with Knowledge Vault.
2009-10-01
If you activate Knowledge Vault's second ability, all that happens at that time is that you pay a cost of . As the ability resolves, you must sacrifice Knowledge Vault. This is mandatory. If you are able to do so, you discard your hand and put all cards exiled with Knowledge Vault into their owners' hands. If you aren't able to do so because Knowledge Vault left the battlefield or changed controllers before the ability resolves, nothing happens.
2008-10-01
You can activate the second ability any time you have priority, including in response to itself. However, you will only be able to sacrifice the Vault as the first such ability resolves.