Vivenne Medrano founded the
animation studio SpindleHorse, under which the pilot for
Hazbin Hotel, the
pilot and first two seasons of
Helluva Boss, and several
animated shorts would be released. Medrano serves as the director, lead writer and lead character designer for SpindleHorse. In an interview with
Cartoon Brew, she said that much of the
Hazbin Hotel pilot was funded by money from her
Patreon, rather than income from YouTube's algorithm. The company
Horseless Cowboy assisted Medrano with voice casting during the first season of
Helluva Boss, with
Richard Steven Horvitz serving as the voice director. Cartoon Brew described her as a "paragon of indie success in animation". In October 2019,
the pilot episode of Hazbin Hotel was released on Medrano's YouTube channel. In November 2019, the
pilot episode of Helluva Boss was released to her YouTube channel as well. On December 25, 2019, a short entitled "Holidaze" was released. In July 2020, Medrano released an animated music video for
Hazbin Hotel called "Addict", featuring the Silva Hound song of the same name. In August 2020,
Hazbin Hotel was picked up for a full series by
A24.
Animation Magazine said that A24 was taking a "bold step" by picking up the series. In 2023, scholar Ben Mitchell described Medrano's
Hazbin Hotel and
Helluva Boss as series which were "sensationally popular" and an effective use of Patreon to subsidize the show's art "through monthly tiered payments".
Hazbin Hotel would go on to be released in January 2024 to critical acclaim. On September 30, 2020, Medrano released an animated short film titled "Bad Luck Jack", based on her webcomic
ZooPhobia. The short was nominated for and won for a
Ursa Major Award in the "Best Dramatic Short Work" category. The short was also listed as a "Recommended Anthropomorphic Dramatic Short Work" on the Ursa Major Award website. From 2020 to 2021, Medrano released several "Voxtagram" animated clips of the characters of
Hazbin Hotel and
Helluva Boss in a
crossover slice-of-life setting to a series of in-character
Instagram accounts run by SpindleHorse employees, alongside normal posts of character art depicting characters'
selfies. In August 2025, Medrano announced the creation of an Australian division of SpindleHorse, called
SpindleRoo. Its first production was a pilot for an animated adaptation of the webcomic
Homestuck. It was the first SpindleHorse project not built around Medrano's stories or characters. She expressed her excitement for this project to
Polygon in a September 2025 interview, saying it will be "very experimental" and called it a "test pilot" for many aspects, including "the studio, the process, a new style, [and] a new technology," adding that audience reaction will determine whether studios are interested in developing it into a full animated series, or if it will be continued on her YouTube channel. She also told the publication that she hoped that the project would open the door for SpindleHorse working with other creators and "more original projects", to support other voices apart from her own ideas. == Animation productions ==