Eyeless Watcher

Oracle Text

Devoid (This card has no color.)

When Eyeless Watcher enters the battlefield, put two 1/1 colorless Eldrazi Scion creature tokens onto the battlefield. They have "Sacrifice this creature: Add C to your mana pool."

Card Rulings

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.
8/25/2015 Eldrazi Scions are similar to Eldrazi Spawn, seen in the Zendikar block. Note that Eldrazi Scions are 1/1, not 0/1.
8/25/2015 Eldrazi and Scion are each separate creature types. Anything that affects Eldrazi will affect these tokens, for example.
8/25/2015 Sacrificing an Eldrazi Scion creature token to add {1} to your mana pool is a mana ability. It doesn’t use the stack and can’t be responded to.
8/25/2015 Some instants and sorceries that create Eldrazi Scions require targets. If all targets for such a spell have become illegal by the time that spell tries to resolve, the spell will be countered and none of its effects will happen. You won’t get any Eldrazi Scions.