Impromptu Raid is a rare Enchantment card from Shadowmoor (SHM), collector number 209. Current market price: $0.38 (foil $3.16), TCGplayer market prices via Scryfall.
{2}{R/G}: Reveal the top card of your library. If it isn't a creature card, put it into your graveyard. Otherwise, put that card onto the battlefield. That creature gains haste. Sacrifice it at the beginning of the next end step.