Caelix, the Void Mage

Devoid (This card has no color.)
Whenever a colorless creature enters the
battlefield or a creature with Devoid enters the battlefield, create a void token. (Void tokens are
tokens that have: "{t}, Add {c}." and "{t}, sacrifice
void: target creature gains Devoid and gets
+1/+1."
Non-colorless creatures deal half the damage they
would usually deal rounded down.