Cheapest priced copy (Urza's Legacy): $1.29 at Card Kingdom, near mint, their price list as of .
Lurking Skirge 
Enchantment · Rare · Urza's Legacy · #55
When a creature is put into an opponent's graveyard from the battlefield, if this permanent is an enchantment, it becomes a 3/2 Phyrexian Imp creature with flying.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $1.29 to $16.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Urza's Legacy | 55 | Rare | $1.29 | $16.99 |
One ruling from Wizards of the Coast
- 1 August 2008A noncreature permanent that turns into a creature can attack, and its {T} abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn't matter how long the permanent has been a creature.