Grub, Storied Matriarch // Grub, Notorious Auntie

Two Grubs, one card, and a single mana pivots between them in either direction. That toggle is the whole engine: the Matriarch pays red to become the Auntie, and the Auntie pays black to flip back, so the card is never welded to one role and can lean toward whichever half your board needs. The Matriarch is the refuel side, buying back a Goblin from the yard each time she enters or transforms into that face; because the trigger keys off transforming into Matriarch, it is the black-side flip that rebuilds your hand. The Auntie is the payoff, converting blight into a combat blowout: blight one, then stamp out a tapped, attacking copy of the blighted creature that sacrifices itself at the end step. That copy takes the card's printed values (no borrowed counters, auras, or pump), so the correct target is a creature whose base body already rewards being doubled for the swing. What keeps the two faces from folding into an instant-speed loop is where the flips are gated: both are locked to your precombat main phase, so you get exactly one directional choice per turn, paid in the correct color. Parking on a single side is trivial; earning the full loop asks the deck to feed a Goblin graveyard and a blight package at the same time, two build constraints pulling in different color directions.