Pithblot, I think you have it.
The Transavia Airtruk (warning: may frighten small children)
From Australia, one could reasonably assume it was designed, say, by a couple of locals in a Darwin bar shortly
after passing out. It was however crafted by an Italian ex patriate, who presumably was deported from his home country on the grounds that his sense of style amounted to treason.
It has a sesquiplane layout. I'm not really sure what this aeronautical term means, but I'm guessing the gist is "extremely unpleasant".
Starting out with an IO-520, later variants reached 400hp with an IO-720. This could only have been a good thing, as it meant you could get one out of sight quicker than ever before.
Having hosted the creation of this monstrosity, the Australians and their NZ manufacturing cohorts also managed to ship the "flying midair collision" to countries such as Denmark and Kenya, despite never formally declaring war.
A total of 118 were built from 1966 to the eighties, although how many were destroyed for humanitarian reasons is not known. It has been said that the Airtruk isn't merely the ugliest aeroplane ever, "it's the ugliest
anything, ever."
If there is an aircraft more ugly than this, then I may need sedation before seeing the pictures.