Roku's Mastery is a uncommon Instant card from Avatar: The Last Airbender Eternal (TLE), collector number 243. Current market price: $0.18 (foil $0.36), TCGplayer market prices via Scryfall.
Roku's Mastery deals X damage to target creature. If X is 4 or more, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)