Necromantic Selection

Oracle Text

Destroy all creatures, then return a creature card put into a graveyard this way to the battlefield under your control. It's a black Zombie in addition to its other colors and types. Exile Necromantic Selection.

Card Rulings

11/7/2014 Necromantic Selection doesn’t overwrite any of the creature’s colors or types. Rather, it adds another color and another creature type.
11/7/2014 If the creature is normally colorless, it will simply become black. It can’t be both black and colorless.