The full "Halloween Ritual" achievement is an 8-part process that tracks your progress as you obtain these specific characters and items:
Engaging in Halloween-themed crafts can be a fun way to get into the spirit of the season. You can make decorations, costumes, or gifts for friends.
Activate the redstone clock. The cracked piston will fire unevenly. Count the pulses. On the (not the third or fifth), drop a single piece of sugar into the pit. This "sweetens the crack."