Devoid (This card has no color.)
Whenever a creature you control deals combat damage to a player, you may draw a card.
: Target creature can't be blocked this turn. ( represents colorless mana.)
1/22/2016 Activating Deepfathom Skulker’s last ability after it’s been legally blocked won’t change or undo that block. The declare attackers step is the last time you can activate the ability and have it be effective.