Treehoppers are related to cicadas and leafhoppers. There are about 3,200 species of treehoppers and over 400 biological classifications of them.
Large family, yes.
The treehopper family are known for their extraneous gear and alien look ─ the Brazilian Tree Hopper is not the weirdest by far, there are some that are weirder ─ because sporting extra horns and thorns and spiny hairs are always good preventive measures from getting swallowed by predators. In the case of the Brazilian Treehopper, the helicopter-like ball appendages with the spines are hollow chitin, and may act as sensory bristles, mate-attracting accessories or simply gag-inducing outgrowths for the purpose of making themselves a difficult meal for others. (Featured pic from listverse).
Watch a Whole Bunch of Treehoppers in Action!