Cliffrunner Behemoth

A 5/3 for four mana is the kind of fragile-but-large beater green has always sold at a discount: big enough to threaten, soft enough that anything trades up on it. The two conditional keywords are the whole design conceit, and they cost nothing in mana or building blocks. They simply check your board for a colored permanent in the relevant color. Control a red permanent and the haste lets it swing the turn it resolves, getting damage in before removal can answer. Control a white permanent and the lifelink converts five power into a five-life swing each combat, offsetting the same thin toughness that makes it a liability. The cleverness is that the abilities ride on board state a three-color aggro deck assembles anyway, so long as you read the requirement correctly: it wants an actual red or white permanent, not a permanent that taps for those colors. A standard dual land is colorless and does nothing here; neither does a Boros Signet, despite its color identity. You need a creature, an enchantment, or another genuinely red or white object on the battlefield. That precision is also the honest cost of the design. In a deck that cannot reliably present both colors, this is a vanilla body with upside that never arrives, and the ceiling lives entirely in the colors you bring alongside it rather than in anything the card does on its own.