Rope of climbing

A 60-foot-long rope of climbing is no thicker than a slender wand and weighs no more than three pounds, but it is strong enough to support 3,000 pounds. Upon command, the rope snakes forward, up, down, or any other direction, at 10 feet per round and attaches itself securely wherever desired. It returns or unfastens itself in a similar manner. A rope of climbing can also be commanded to knot itself. This causes large knots to appear at 1-foot intervals along the rope. Knotting shortens the rope to 50-foot length until the knots are untied. One end of the rope must be held by a character when its magic is invoked.