Lava Spike

The whole design exists to do one thing and refuse to do anything else: it cannot kill a creature, cannot break up a combat. Lightning Bolt is the baseline three-damage burn spell, and most of red's cheap removal trades some of that flexibility for a rider or a discount. This trades all of it. The reward for accepting "target player or planeswalker" and nothing more is a clean, undiluted three damage to the face for a single mana, which makes it the purest reach-the-opponent tool red has at this rate. A deck that runs it has stopped pretending to care about the battlefield: every point goes upstairs, every copy is interchangeable with a burn spell, and the only math that matters is twenty divided by three. The Arcane subtype is a quiet inheritance from when it was first printed, plugging into the splice mechanics that surrounded it, though that synergy stopped being the reason anyone ran it long ago. What keeps it relevant is exactly its inflexibility: when the plan is to win before the board state matters, a removal-capable burn spell is overqualified, and the spell that can only hit players and planeswalkers is the one that does the job without temptation.