Stalwart Successor

Menace (This creature can't be blocked except by two or more creatures.) Whenever one or more counters are put on a creature you control, if it's the first time counters have been put on that creature this turn, put a +1/+1 counter on that creature.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6oa4m06r41pb1h0fwe54vq.