Quicksilver, Brash Blur is a rare Legendary Creature — Mutant Hero card from Marvel Super Heroes (MSH), collector number 412. Current market price: $1.15 (foil $0.50), TCGplayer market prices via Scryfall.
If Quicksilver, Brash Blur is in your opening hand, you may begin the game with him on the battlefield. Haste Power-up — {4}{R}: Put a +1/+1 counter and a double strike counter on Quicksilver. (Activate each power-up ability only once. Reduce the cost by his mana cost if he entered this turn.)