This is meant as some sort of mini-series to feature some lesser known birds with weird beaks. Perhaps I will also include some birds which seem more familiar, but whose weird beak features are usually missed.
I start with the violet turaco (Musophaga violacea), a member of the diverse turaco family from tropical and subtropical Africa. In this birds the beak extends in a bulbous shape over the frontal skull area and forms a contiunous shield like structure.
Violet turaco (Musophaga violacea) at the Zoological Institute Tübingen
If you take a close look, you can also see small serrations in the anterior part of the upper beak.
Violet turaco from Wikipedia