Barbed Lightning

Entwine is the clause that earns the deck slot: pay the surcharge and the same instant that kills a creature also throws three more at a face or planeswalker, six total damage that doubles as a removal spell from one card and one cast. The two base modes are deliberately plain, three damage to a creature or three to a player or planeswalker, so most of the time this lives as a modest removal spell and only snaps into a finisher when the extra mana is sitting untapped. That is the whole point of the keyword: a narrow effect at a cheap rate now, or a wider one later for a premium you choose to pay, with the total cost steep enough that you rarely entwine early. Instant timing matters more than the rate. Held up, it kills a blocker at the worst moment for the defender, or it idles as reach until the opponent taps low and the entwined cast ends the game out of nowhere. As design, it is a clean piece of modal flexibility from an era when red's removal usually committed to a single target type the moment you wrote it on the card; folding "kill a thing" and "burn a face" into one decision, and then letting you buy both, is what gives the card a longer shelf life than its damage numbers suggest.