A Rattleback is a phenomenal physical curiosity. No matter how you spin the semi-ellipsoidal top it will fight back and only spin in one direction, slowing and reversing as if by magic. Even when you tap the top and it chooses to spin on its own in only one direction. This violates the angular-momentum conservation law of physics, exciting and mysterious! Comes in a range of colours, please message us if you have a colour preference.
