Movie Connection Problem

I want to change the description of Spin-Off from the game Undertale, so far it says "Fanmade Sequel" and I want to rename "Based on the video game". The reason is that the webseries Glitchtale is based on Undertale and it's not canon either, it's a fanmade animation series by a YouTuber Camila Cuevas, there is still an error "Unable to verify" by the way. (And one question: Why does it say Spun-off from instead of Spin-off from?)