5) The Death Star in 'Star Wars'
Any weapon as big as a planet with the word "death" in the title is always going to be a beast. It certainly lives up to its name when it annihilates an entire planet in one just shot.
The destruction of the Death Star was infamously mocked in Kevin Smith's 'Clerks' proving that you wouldn't want to be one of the innocent workers painting the gents of Darth Vader's vast empire when the good guys blew it up.