Mindwhisker is a uncommon Creature — Rat Wizard card from Bloomburrow (BLB), collector number 60. Current market price: $0.18 (foil $0.35), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, surveil 1. (Look at the top card of your library. You may put it into your graveyard.) Threshold — As long as there are seven or more cards in your graveyard, creatures your opponents control get -1/-0.