
DevourDevourAs this creature enters, you may sacrifice any number of creatures. This creature enters with that many +1/+1 counters on it. 1 (As this creature enters, you may sacrifice any number of creatures. This creature enters with that many +1/+1 counters on it.)
At the beginning of your end step, create a number of 1/1 black and green Pest creature tokens equal to the number of +1/+1 counters on this creature. They have "When this token diesdiesA creature dies when it goes from the battlefield to a graveyard. Being exiled or returned to hand is not dying., you gain 1 life."
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Read from the rules text. A card that enables a keyword makes or is the thing; a card that rewards it gets better when you have it. Two cards interact when one enables what the other rewards.