Stensia Uprising is a rare Enchantment card from Innistrad: Double Feature (DBL), collector number 445. Current market price: $0.31 (foil $1.80), TCGplayer market prices via Scryfall.
At the beginning of your end step, create a 1/1 red Human creature token. Then if you control exactly thirteen permanents, you may sacrifice this enchantment. When you do, it deals 7 damage to any target.