One of the big 3. Along with Underswap and Underfell, Outertale is one of the most well known AUs. It was the 1st AU with a basic change (being outside of the underground).
“Stars is the Outertale version of Gaster according to Bun-bunmuse. He and Fell are currently...W. D. Gaster/Outertale/GasterGang
“"An Inktale AU that has more than one character!" Outerink is a combination of Inktale and...Outerink