Nightfire Giant

A mono-black creature that spends the whole card asking for red without ever demanding it. The mana cost is a clean five with a single black pip, so any black deck can cast it as a 4/3 beater and lose nothing by ignoring the rest of the text. The two rewards below are the pitch to two-color builds, but they pay out along different tracks. The static bonus is strict: it checks specifically for a Mountain on the battlefield, so a red splash off dual lands without basic land types or off mana rocks leaves the frame at 4/3. Fetch an actual Mountain and it grows to 5/4. The activation is looser: it needs red mana from anywhere, which means the ping can come online in a deck that never runs a single Mountain and never triggers the size bump. That asymmetry is the quietly interesting part of the design: the same card wants two subtly different flavors of red access, and a manabase can satisfy one while whiffing the other. Neither reward punishes you for staying mono-black; the static line does nothing without a Mountain, and the ability sits dormant without red to pay for it. The body carries its own weight, so the splash reads as gravy rather than tax, and the ping itself is priced too high to race with: it is grind fuel, a way to convert idle mana into reach, cleanup for small blockers, or slow chip damage across a long attrition game.