Muzzio's Preparations

Hidden agenda (Start the game with this conspiracy face down in the command zone and secretly choose a card name. You may turn this conspiracy face up any time and reveal that name.) Each creature you control with the chosen name enters with an additional +1/+1 counter on it.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6obhgn7sy7pb1h3flcac3u.