Wumpus Aberration

A 6/6 trample for four sits above the green curve, and the cast trigger is the meter that reads the manabase. Unless colorless mana was spent to cast it, the opponent gets to drop a creature from their hand straight onto the battlefield. Devoid keeps the card colorless for other purposes, but it is the check, not the keyword, that decides whether the drawback fires: cast the Wumpus off ordinary green mana and you hand your opponent a free deployment; cast it with a Wastes or a colorless-producing Eldrazi source supplying and the penalty simply never triggers. That makes it a rate card that quietly demands a colorless source to reach its true cost, punishing decks that jam it as a generic beater and rewarding shells built to feed the requirement. The downside also runs on a stack trigger at cast, so the opponent's free creature resolves before the Wumpus itself, which matters when their hand holds something that trades up or blocks the trampler on the crackback. Green fatties have long been sold at a discount against a real cost, but where older ones paid in a sacrifice or a tempo hit to their own side, this one pays by advancing the opponent's board unless you build to switch the penalty off. The beater is a manabase test in disguise.