Code of Constraint is a uncommon Instant card from Ravnica Allegiance (RNA), collector number 35. Current market price: $0.05 (foil $0.36), TCGplayer market prices via Scryfall.
Target creature gets -4/-0 until end of turn. Draw a card. Addendum — If you cast this spell during your main phase, tap that creature and it doesn't untap during its controller's next untap step.