Overblaze

Damage doublers live or die on what they multiply, and this one cares about a specific verb rather than a specific card type: any combat damage, any ping, any one-shot blast from the single permanent you point it at. Target a planeswalker that deals damage and the doubling rides its loyalty ability; target a creature mid-swing and the burst finishes; target a damage-dealing artifact and the same one-target effect reaches well past the usual "your attacker hits twice as hard." The restriction is real: it touches one permanent, not the whole board, which is exactly the leash that keeps a doubler from being a global blowout. The splice clause is where the card actually earns its keep. Pay the splice cost while casting any Arcane spell and the doubling rides along, so an effect too narrow to main-deck on its own gets a second life as a modifier, billed at the moment you already had a reason to cast something. That is the bargain the splice mechanic was built around: a situational card stops sitting dead in hand and instead bolts itself onto a play that was already happening. The payoff scales with how dense your Arcane base is, since every Arcane spell becomes a potential host. The headline number doubles; the real design is the optionality of when, and onto which single permanent, you choose to spend it.