Experimental Frenzy is a rare Enchantment card from Guilds of Ravnica Promos (PGRN), collector number 99p. Current market price: $0.48 (foil $0.53), TCGplayer market prices via Scryfall.
You may look at the top card of your library any time. You may play lands and cast spells from the top of your library. You can't play lands or cast spells from your hand. {3}{R}: Destroy this enchantment.