Spriggan

A Spriggan is a knotty, ugly guardian of buried treasure and ancient earthworks. It may appear small enough to sit on a stone, then swell to giant size when thieves cross the boundary. Spriggans remember ownership through custom and ignore written documents and may defend a hoard whose original keepers have been dead for centuries. Bargaining requires recognizing that memory as a claim.

Swell to Giant: the Spriggan becomes Huge for 3 rounds, recovers 25 HP even above its normal maximum, and its 2d8+3 strike pushes the target 10 ft. HP above its normal maximum vanish when the Spriggan shrinks. It may do this once per encounter.

Boundary Stone: moving the marked stone weakens its claim, reducing its DR by 2, but returning it and offering restitution may end the encounter entirely.