Worst atheistic argument?

[Tiberius]

The creation of the world is the most marvelous achievement imaginable.
The merit of an achievement is the product of (a) its intrinsic quality, and (b) the ability of its creator.
The greater the disability (or handicap) of the creator, the more impressive the achievement.
The most formidable handicap for a creator would be non-existence.
Therefore if we suppose that the universe is the product of an existent creator we can conceive a greater being — namely, one who created everything while not existing.
Therefore, God does not exist.

let's prove nothing and mean it.

That's a parody of the ontological argument. It's never (to my knowledge) been used to prove the non-existence of God, only to demonstrate the problems with the ontological argument itself.