Leyline of Combustion is a rare Enchantment card from Core Set 2020 (M20), collector number 148. Current market price: $0.41 (foil $0.83), TCGplayer market prices via Scryfall.
If this card is in your opening hand, you may begin the game with it on the battlefield. Whenever you and/or at least one permanent you control becomes the target of a spell or ability an opponent controls, this enchantment deals 2 damage to that player.