Cheapest priced copy (Innistrad): $1.49 at Card Kingdom, near mint, their price list as of .
Mirror-Mad Phantasm 
Creature — Spirit · 5/1 · Mythic · Innistrad · #68
Flying
{1}{U}: This creature's owner shuffles it into their library. If that player does, they reveal cards from the top of that library until a card named Mirror-Mad Phantasm is revealed. The player puts that card onto the battlefield and all other cards revealed this way into their graveyard.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $1.49 to $4.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Innistrad | 68 | Mythic | $1.49 | $4.49 |
3 rulings from Wizards of the Coast
- 22 September 2011If no card named Mirror-Mad Phantasm is revealed (possibly because it was a card copying Mirror-Mad Phantasm or it was a token), all cards from that library will be put into their owner's graveyard.
- 22 September 2011You can only activate the ability if you control Mirror-Mad Phantasm, even if you don't own it.
- 22 September 2011If another creature (such as Necrotic Ooze) gains Mirror-Mad Phantasm's activated ability, its owner reveals cards until they reveal a card named Mirror-Mad Phantasm.