Cheapest priced copy (Magic 2013): $0.49 at Card Kingdom, near mint, their price list as of .
Void Stalker 
Creature — Elemental · 2/1 · Rare · Magic 2013 · #77
{2}{U}, {T}: Put this creature and target creature on top of their owners' libraries, then those players shuffle their libraries.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Magic 2013 | 77 | Rare | $0.49 | $0.49 |
3 rulings from Wizards of the Coast
- 1 July 2012You can activate Void Stalker’s ability targeting a creature you control, including Void Stalker itself. In that case, only you will shuffle your library.
- 1 July 2012If Void Stalker leaves the battlefield before its ability resolves, the target creature will be shuffled into its owner’s library but Void Stalker will remain wherever it is.
- 1 July 2012If the target creature is an illegal target when the ability tries to resolve, it won’t resolve and none of its effects will happen. No creature will leave the battlefield and no library will be shuffled.