Cheapest priced copy (Dragons of Tarkir): $0.35 at Card Kingdom, near mint, their price list as of .
Dirgur Nemesis 
Creature — Serpent · 6/5 · Common · The List · #DTK-51
Defender
Megamorph {6}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dragons of Tarkir | 51 | Common | $0.35 | $0.49 |
| The List | DTK-51 | Common | $0.35 | — |
4 rulings from Wizards of the Coast
- 25 February 2015If a face-down creature with megamorph is turned face up some other way (for example, if you manifest a card with megamorph and then pay its mana cost to turn it face up), you won’t put a +1/+1 counter on it.
- 25 February 2015Turning a face-down creature with megamorph face up and putting a +1/+1 counter on it is a special action. It doesn’t use the stack and can’t be responded to.
- 25 February 2015Megamorph is a variant of the morph ability. You can find more information on morph on cards with morph from the Khans of Tarkir set.
- 25 February 2015If an attacking face-down Dirgur Nemesis is turned face up, it will continue to be attacking even though it will have defender.