General Tazri

Oracle Text

When General Tazri enters the battlefield, you may search your library for an Ally creature card, reveal it, put it into your hand, then shuffle your library.

WUBRG: Ally creatures you control get +X/+X until end of turn, where X is the number of colors among those creatures.

Card Rulings

1/22/2016 The last ability checks only Ally creatures you control as the ability resolves. The value of X will be between 0 and 5. Colorless is not a color.
1/22/2016 Once the last ability resolves, the bonus given doesn’t change, even if the number of colors among your Allies does.