Lost Days is a common Instant — Lesson card from Avatar: The Last Airbender (TLA), collector number 62. Current market price: $0.11 (foil $0.23), TCGplayer market prices via Scryfall.
The owner of target creature or enchantment puts it into their library second from the top or on the bottom. You create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")