The adjective patito is often applied to incompetent professionals or institutions. I especially associate it with fly-by-night doctors, perhaps because pato = duck and in English we refer to incompetent doctors as quacks. Un médico patito, a quack (doctor).

Patito is also commonly used to describe diploma mills, schools of questionable quality: una escuela patito, una escuelucha.

Note: For most speakers, patito is invariable: médicos patito, escuelas patito.

Like chafa, patito can be used for talking about low-quality products: las marcas patito(s), bottom-of-the-barrel brands.