You can cut off the head of an egg with an egg top cutter. It can be plastic with a circular cutout and a blade attached to a moving arm. The egg is placed in the cutout, the arm is moved inwards and the head is cut off. It can also be an elongated piece of metal with a circular cutout. The head is removed from the egg with a hinged blade - which also has a pointed protrusion that can serve as an egg piercer.
See also the eggshell cutter. [MOT]