Thunderheads is a uncommon Instant card from Guildpact (GPT), collector number 37. Current market price: $0.05 (foil $0.35), TCGplayer market prices via Scryfall.
Replicate {2}{U} (When you cast this spell, copy it for each time you paid its replicate cost.) Create a 3/3 blue Weird creature token with defender and flying. Exile it at the beginning of the next end step.