This is the Wilson's bird-of-paradise, found exclusively on the tiny islands of Waigeo and Batanta in the Raja Ampat archipelago of West Papua. That turquoise cap isn't made of feathers - it's actually a patch of very brightly coloured bald skin.
Nature is so random. This is what happens after many generations end up following arbitrary instinctive preferences. Mutations cause physical and behavioral changes. No master designer required.