Manifold Mouse is a rare Creature — Mouse Soldier card from Bloomburrow (BLB), collector number 318. Current market price: $0.92 (foil $1.08), TCGplayer market prices via Scryfall.
Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.) At the beginning of combat on your turn, target Mouse you control gains your choice of double strike or trample until end of turn.