Doubling Season is a rare Enchantment card from Ravnica: City of Guilds (RAV), collector number 158. Current market price: $41.66 (foil $133.34), TCGplayer market prices via Scryfall.
If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead. If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.