Smoke Shroud is a common Enchantment — Aura card from Foundations Jumpstart (J25), collector number 361. Current market price: $0.33, TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature gets +1/+1 and has flying. When a Ninja you control enters, you may return this card from your graveyard to the battlefield attached to that creature.