Usually some type of machine consturcted (by evil) for the purpose of:
- Destroying The World
- Ruling The World
- Killing people
- Enslaving (ruling) people
As a general rule, all inventions of evil villains must have the suffix "-tron" or "-tor", and/or be a ray of some sorts. For example: The orgasmotron, megatron doomsday machine, the annihilator, the bikini ray, pimp ray, etc.