what's the wildest or most outrageous AU you've made that you still enjoy? are there any AUs you've made that make you uncomfortable looking back?
Easily the most outrageous (affectionate) AU I've ever been a part of was Full Circuit with @sialiapromethean
Like I consider myself prone to bizarre fetishes and self-indulgent AUs but with Trin's help things went WILD extremely quickly. The entire AU is us putting literally EVERY ship we can think of in one overcomplicated polycule and getting crazier from there. Early on we established cybernetic upgrades and being able to transform into specific things by voring the chaos emeralds like Sonic becoming a motorcycle, Shadow becoming a laser cannon, etc. Then things get even crazier with 9 minute hyper pregnancy, Metal impregnating Shadow's heart, Surge have a single kid with the entire Sonic Underground trio as the biological fathers, and them adopting Mephiles because, as previously stated, a full grown copy of Shadow popping out of someone's womb is among the less weird pregnancies they've had.
As for AUs that make me uncomfortable looking back... not really. If anything I've gotten significantly weirder over time so my more recent AUs would disgust younger me. Like my most recent AU has a focus on Shadails of all things. (In case you're wondering, the premise is that 10 years after canon Shadow and Tails are "close friends" that everyone but them thinks are dating, when Shadow starts going through alien puberty and becomes a Doom monster that is easily triggered by certain smells. Tails makes a special gas mask for him that filters out potential triggers but can also intentionally trigger certain effects whenever he wants)
Closest thing I can think of is an AU that I helped a friend with that features some kinks I'm not particularly into, but even then I wouldn't say it makes me "uncomfortable"