Horadric Lutefisk Cube
Horadric Lutefisk Cubes are devices found in the dungeon. When right-clicked, they open a crafting window with only one square. Anything placed into the window becomes a Lutefisk, which makes tithing large amounts of lutefisk easier.
Attempting to transmute another Horadric Lutefisk Cube or the same Cube being used creates an explosion that is capable of killing early-game characters outright.
Trivia
The Horadric Lutefisk Cube is a reference to Blizzard Entertainment's Diablo 2, in which the Horadric Cube was used to combine objects in order to (mostly) make stronger and better equipment.