This Demogorgon figure is released by Funko in their POP! TV x Stranger Things 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 Funko POP! x Stranger Things series features characters from the sci-fi horror TV series. The first season focuses on the disappearance of a young boy, and the appearance of a psychokinetic girl, who helps his friends in their search, while the boy's older brother, his mother, and the town police chief start their own investigations.