Plague of Vermin is a rare Sorcery card from Shadowmoor (SHM), collector number 73. Current market price: $20.39 (foil $70.88), TCGplayer market prices via Scryfall.
Starting with you, each player may pay any amount of life. Repeat this process until no one pays life. Each player creates a 1/1 black Rat creature token for each 1 life they paid this way.