Lethal Scheme is a rare Instant card from Tarkir: Dragonstorm Commander (TDC), collector number 184. Current market price: $0.24, TCGplayer market prices via Scryfall.
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) Destroy target creature or planeswalker. Each creature that convoked this spell connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature.)