Mask of the Mimc + protection from Blue

[Greenpoe]

If you have only one creature (Progentius) and cast Mask of the Mimc, does it work? Can Mask of the Mimic be used on Progentius so you replace him with another Progentius, even though he has protection from everything? I thought it would work because it looks like you're basically targeting yourself instead of a given creature, so you are forced to sacrifice the only creature you would control to play the spell.

[cdr]

It helps to read the Oracle wording of the card, carefully.


Mask of the Mimic U
Instant
As an additional cost to cast Mask of the Mimic, sacrifice a creature.
Search your library for a card with the same name as target nontoken creature and put that card onto the battlefield. Then shuffle your library.

As a cost play the card, you have to sacrifice a creature. You can choose to sacrifice the same creature you target, because costs are paid after targets are chosen, but then Mask would be countered upon resolution for lack of a target.

If you read the card, it targets a nontoken creature, so targeting Progenitus is obviously not an option.