Shy Town is a common Plane — Chicago card from Black Lotus Unknown Planechase (PUNK), collector number PLA007. Current market price: $19.99, TCGplayer market prices via Scryfall.
Whenever you planeswalk here and whenever chaos ensues, for each opponent, put a shy counter on up to one target creature they control. That creature becomes a Coward in addition to its other types. At the beginning of your upkeep, create a 2/2 red Warrior creature token with haste and "Cowards can't block Warriors."