Santa Claus

To climb up the rope, Santa Claus utilises the change in friction force in 'bent down' and 'straighten up' position of his body.

Pulling the string down brings about straightening up of the Santa's body - the angle at which the string is coiled around the peg gets sharper, the friction at the legs gets reduced, but still it is static and it is greater compared to the dynamic friction affecting the movement of the hands.

When at last Santa straightens his body up, the friction at the legs gets is lesser than (now static) friction at the hands: the legs move upwards.

Of course, the grip of the hands on the string should not be too strong, so that they still can slide along the string when the legs are motionless and not too loose, so that they can remain motionless, when Santa bends down after pulling himself up.