Unstable Experiment is a common Instant card from Marvel Super Heroes Commander (MSC), collector number 789. Current market price: $0.29 (foil $0.24), TCGplayer market prices via Scryfall.
Target player draws a card, then up to one target creature you control connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature.)