A more original and creative metaphor for saying something is unbelievably shit. It suggests it is shit off the floor and picked up off the floor with a shovel by a homeless or very working class person. Commonly used by the cool kids at school mostly against minecraft nerds (see minecraft nerd) to remind them how fucking awful minecraft is.
Ross: 'Sup minecraft nerds
The Minecraft Posse: go away, we are discussing the new minecraft graphics pack beta version 18.104.22.168.4
Ross: minecraft is shit on a shovel, you benders