Swarm Surge

Oracle Text

Devoid (This card has no color.)

Creatures you control get +2/+0 until end of turn. Colorless creatures you control also gain first strike until end of turn.

Card Rulings

8/25/2015 A colorless creature given first strike by Swarm Surge won’t lose first strike if it stops being colorless later in the turn.
8/25/2015 Cards with devoid use frames that are variations of the transparent frame traditionally used for Eldrazi. The top part of the card features some color over a background based on the texture of the hedrons that once imprisoned the Eldrazi. This coloration is intended to aid deckbuilding and game play.
8/25/2015 A card with devoid is just colorless. It’s not colorless and the colors of mana in its mana cost.
8/25/2015 Other cards and abilities can give a card with devoid color. If that happens, it’s just the new color, not that color and colorless.
8/25/2015 Devoid works in all zones, not just on the battlefield.
8/25/2015 If a card loses devoid, it will still be colorless. This is because effects that change an object’s color (like the one created by devoid) are considered before the object loses devoid.