Friendly Rivalry

A bite spell with an optional second bite. The green-red baseline is intact: your creature deals damage equal to its power to something you don't control, the one-way removal template that has kept green cheap and color-agnostic at killing things. The wrinkle is the "up to one other" clause, which lets a legendary creature you control pile its power onto the same target, folding two hits into one instant-speed answer. That optionality is the whole design: cast it off a single creature and it plays as a clean, no-cap bite; cast it with a legendary body backing it and the damage doubles up, biasing the card toward boards already anchored on a marquee legend or a heavy legendary threat. Because the payload is raw creature power funneled at one creature rather than a fixed burn number, the answer sizes itself to the board you built, and it can outreach the small-damage bites green usually gets. The restraint is that the effect only scales as far as your creatures are big: from an empty battlefield it does nothing, and against a fat body a lone attacker may not close the gap. The legendary rider is the reward for playing to that theme rather than a requirement to use the card at all, which keeps a two-mana kill-anything at instant speed honest without ever forcing you to hold it.