Code of Constraint 

Instant
Artist:
Ekaterina BurmakShare:
Text:
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.
Rulings:
- 1/25/2019 If the target creature is an illegal target by the time Code of Constraint tries to resolve, the spell doesn’t resolve. You don’t draw a card.
- 1/25/2019 Code of Constraint can target a creature that’s already tapped. If you cast it during your main phase, that creature won’t untap during its controller’s next untap step.
- 1/25/2019 Addendum abilities of instant spells apply while the spell is resolving, not immediately after casting it. If the spell is countered, you don’t get the addendum bonus. For example, if you cast Sphinx’s Insight during your main phase, you gain 2 life during its resolution, after you draw two cards.
- 1/25/2019 If a spell with an addendum ability is copied, the copy won’t give you the addendum bonus. This is because the copy wasn’t cast at all.
Legality:
- standard: Not legal
- future: Not legal
- frontier: Legal
- modern: Legal
- legacy: Legal
- pauper: Not legal
- vintage: Legal
- penny: Not legal
- commander: Legal
- 1v1: Legal
- duel: Legal
- brawl: Not legal
- oldschool: Not legal
- historic: Legal
- pioneer: Legal
- gladiator: Legal
- premodern: Not legal
- historicbrawl: Legal
- paupercommander: Not legal
- alchemy: Not legal
- explorer: Legal
- predh: Not legal
- oathbreaker: Legal
Sets:
-
Ravnica Allegiance #35 (uncommon)