Flavor Disaster

As a permanent with negamorph is turned face up, put a -1/-1 counter on it if its negamorph cost was paid to turn it face up. If it’s turned face up in any other way than paying its negamorph cost, you won’t put a -1/-1 counter on it.

For many playtest cards, you’ll need to make a generous assumption that basic game rules would be updated to allow them to work. The Mystery Booster 2 Playtest Card Notes section (reproduced here in individual Gatherer rulings) provides guidance for fitting these cards into the existing rules structure.

The creature spell is a 2/2 creature spell that has no name, mana cost, or creature types. The resulting creature is a 2/2 creature that has no name, mana cost, or creature types. Both the spell and the resulting creature are colorless and have a mana value of 0. Other effects that apply to the spell or creature can still grant it any characteristics it doesn’t have or change the characteristics it does have.

If Flavor Disaster is no longer on the battlefield when its second ability resolves, use its power as it last existed on the battlefield to determine the value of X.

The face-down spell has no mana cost and has a mana value of 0. When you cast a face-down spell, put it on the stack face down so no other player knows what it is, and pay {3} to cast it. This is an alternative cost.

The value of X is determined only once, as Flavor Disaster’s second ability resolves.