How to Start a Riot is a common Instant — Lesson card from Avatar: The Last Airbender (TLA), collector number 140. Current market price: $0.15 (foil $0.23), TCGplayer market prices via Scryfall.
Target creature gains menace until end of turn. (It can't be blocked except by two or more creatures.) Creatures target player controls get +2/+0 until end of turn.