An Invisible Paint Brush is one of the least expensive brushes in Neopia, except for the basic colored ones. They normally cost about 85,000NP from the shop wizard. They are not very sought after as, like the title suggests, it turns your pet invisible.
There is also a random event which can turn your pet invisible. Invisible pets can be customised, so they can wear clothes, making some look quite hilarious! (Note: Not all invisible pets can wear all clothes. One that can is the Kau.) All invisible Neopets technically look the same.
Pets this Paint Brush can be used on