False Appearance. While the galeb duhr remains motionless, it is indistinguishable from a normal boulder.   Rolling Charge. A galeb duhr gains a 6 squares speed when rolling, which increases to 12 squares if rolling downhill. If the galeb duhr rolls at least 4 squares straight toward a target and then hits it with a slam attack on the same turn, the target takes an extra 7 ( 2d6 ) bludgeoning damage. If the target is a creature, it must succeed on a DC 16 Strength saving throw or be knocked prone.