This Buttercup vinyl figure is released by Funko in their POP! Animation x Powerpuff Girls vinyl figure series.
Funko POP! is a crossover vinyl figure series by Funko and other famous franchises such as Disney, Pixar, DC Comics, Marvel Comics, Simpsons, South Park, Uglydoll, etc. Each POP! figure is about ~3" to ~5" tall and crafted in a Japanese anime/manga super-deformed style (NOTE: due to the unique design of each character, the actual size of the figures may be smaller or bigger than stated).
The POP! Animation x Powerpuff Girls series features characters from the animated TV show that centers on Blossom, Bubbles, and Buttercup, three girls with superpowers, as well as their father, the brainy scientist Professor Utonium, who all live in the fictional city of Townsville, USA.