Unbreakable Formation is a rare Instant card from Ravnica Allegiance (RNA), collector number 29. Current market price: $0.81 (foil $2.50), TCGplayer market prices via Scryfall.
Creatures you control gain indestructible until end of turn. Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.