Rule 93
This rule states that if you see a chicken/duck you got to hit it with a shovel.
This expression sprung up from the "famous" youtuber slyfoxhounds (xXSlyFoxHoundXx, part of a group called The Creatures) Minecraft videos. He used the fact (before some updates) that if you hit a chicken with a shovel, you were given the loot 1 or 2 feathers and a piece of chicken, wich can be consumed.
person 1: Oh, look! A chicken!

Person 2:I envoke Rule 93! *hits it with shovel*