Reaper King

Five-color color identity meets one of Magic's most ignored creature types, and the collision is the whole pitch. The lord bonus is rote tribal glue; the real engine is the destruction trigger, which turns every Scarecrow that follows onto the battlefield into a removal spell. The clause does not discriminate, so a single token-maker or a flicker effect converts the King from a 6/6 beater into a permanent-killing machine that does not stop at lands, planeswalkers, or your own creatures if you want to chain it. What makes the tribe cooperate is that Scarecrows are artifacts as often as not, which means colorless filler and token generators feed the trigger without warping a manabase. The cost reads as a gag and works as elasticity: every pip is hybrid, accepting either two generic mana or a single colored symbol, so the printed value of 10 can be paid with ten of anything off a colorless pile, or shaved to as little as five if a deck can spend one of each color. That is the design's reason to exist. A creature whose identity touches all five colors should be castable from any of them, and the hybrid framing means the King never demands the full WUBRG spread to hit the table; it simply rewards a deck that can. The destruction clause is what pays back the deck for assembling the Scarecrows in the first place, and the elastic cost is what keeps the assembly from being a tax.