It's called the PZL M-15 Belphegor & Woj is correct, it's an agricultural aircraft (boy, that's an understatement!)

Apparently it was very effective against bugs, it scared the hell out of insects, livestock & small children.

Strangely (thankfully?) no one has felt the need to model one.

As well as being arguably the world's ugliest jet it's also the world's slowest, top speed 125 mph. - John.