Cheapest priced copy (Morningtide): $0.69 at Card Kingdom, near mint, their price list as of .
Grimoire Thief 
Creature — Merfolk Rogue · 2/2 · Rare · Morningtide · #35
Whenever this creature becomes tapped, exile the top three cards of target opponent's library face down.
You may look at cards exiled with this creature.
{U}, Sacrifice this creature: Turn all cards exiled with this creature face up. Counter all spells with those names.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.69 to $7.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Morningtide | 35 | Rare | $0.69 | $7.99 |
5 rulings from Wizards of the Coast
- 1 April 2008If a split card is turned face up, the ability counters all spells with the same name as either side of that split card.
- 1 April 2008The only cards you turn face up are the cards exiled with the Grimoire Thief that was sacrificed.
- 1 April 2008The last ability counters all spells on the stack with any of the appropriate names, no matter who controls them.
- 1 July 2013Once a player gains control of Grimoire Thief, that player can look at all cards it exiled, even if those cards were exiled while someone else controlled Grimoire Thief.
- 1 July 2013Once a player is allowed to look at the exiled face-down cards, that player may continue to do so even after Grimoire Thief leaves the battlefield or another player gains control of it.