Rhonas's Monument

The cost-reducer half is the obvious draw, but the second clause is what pays for a mono-color tax that would otherwise be too cheap. Both halves come online the moment the Monument resolves: any green creature you cast afterward that same turn is a mana cheaper, and any creature spell at all hands a creature you control +2/+2 and trample. That split target is deliberate. Only green spells qualify for the discount, but the pump trigger fires on every creature you cast, so a splashed body still feeds the engine without earning the tax break. The trigger compounds with each spell, which turns a curve of bodies into a chain of combat threats: the eighth creature is not just another blocker but another +2/+2 hunting for a face, and the trample clause keeps that buff from dying to a single chump. This was one of five Monuments, each a legendary artifact pairing a color's creature-cost reduction with a cast trigger flavored for its plan; green's version was tuned for the deck that floods the board and wants the extra reach to close before the ground stalls. The cost, then, is not tempo (the reductions and pumps start working immediately) but commitment. The Monument has no body of its own, so its value lives entirely downstream, in the creatures that follow it. It rewards a deck already resolved to overcommit and gives that plan a way to punch through rather than merely pile up.