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 will snake forward, upward, downward, or any other direction at 10 feet per round and attach itself securely to whatever deswired.  It will return or unfasten 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 a 50-foot length until the knots are untied.  One end of the rope must be held by a character when its magic is invoked.