The clove hitch is a ‘stopper knot’ used in the middle of a rope to stop either end of the rope from being pulled. It stops the rope from moving either direction, to some degree. As one side pulls, the friction and tension of the rope stops it. The same is true for the other side. Getting the knot undone is fairly simple as long as there is slack on at least one side. It is also a weight bearing knot that can be trusted.