Gargoyle Sentinel

A wall that pays its own way back into the attack. The defender keyword usually marks a creature as a permanent blocker, a body that trades attacking forever for cheap, oversized defense. Here the restriction is rented rather than sold: three mana, any turn, peels off defender and bolts on flying until end of turn, turning a 3/3 stone guard into a 3/3 evasive threat at will. The structure rewards a draw that floods on mana late, where a card that did nothing but block early can spend a surplus to start clocking the opponent. The 3/3 body is the quiet enabler: large enough to wall most early aggression, large enough that three points in the air actually matters when the gargoyle finally takes flight. As a colorless artifact, it slots into any deck that wants a turn-three blocker without committing to a defensive game plan, which is exactly the flexibility a mono-color or off-color shell can rarely buy. The design is a clean answer to a perennial problem with walls: they are dead cards once the board stabilizes. This one converts that dead weight into reach, and the activation cost is the lever that keeps it honest, steep enough that flipping it on is a real decision about your mana rather than a free swing.