Jund Battlemage

The Battlemage cycle's whole conceit was an uncommon-rarity body wearing two of a shard's three colors as off-color activated abilities, and this one wears Jund's outer thirds: black's reach and green's bodies, both bolted onto a red creature. Neither half is impressive in isolation, which is exactly what a common built for small repeatable work is supposed to be. The black activation is a tax-rate drain, one life at a time at the cost of a black mana and a tap; the green activation is a slow Saproling factory at a green mana per body. What ties them together is the shared tap symbol: this is one card with two mutually exclusive mana sinks, and each turn you pick which clock you want, the attrition one or the board-building one. That tension is the design idea, a creature that converts surplus mana of two colors it cannot itself produce into either incremental life loss or incremental width, and never both at once. The card it most wants is a deck with mana to burn and time to spend it, which is precisely the grindy three-color midrange shell its shard was built around.