To add to the confusion: For 2 weeks/year I help out the local ballet studio with stage crew. We have this big white backdrop curtain, and colorful lights are pointed directly at the curtain to make dramatic and moody changes to the background during certain dances. When I heard the name of these, I assumed it was the "psyche curtain" and "psyche lights" because that's how it is pronounced.

Turns out the box is marked "Cyc." I have to assume that the people that sold the curtain are way less amateur than I am, so I would like to add this third potential spelling.

I had always assumed it was humorously mis-spelling the word. Like people who would spell it "kool".

This is truer than you might think. A lot of slang developed out of a need to express oneself without having the vernacular (or even desire) to clearly articulate. It leads to innovating interesting (and in some cases more practical) new ways to say something in a way others (typically in your in-group) can understand easily.

I suspect a lot of that crazy Gen Z stuff comes from kids getting into social media well before fully developing their own social skills, so it just started manifesting through terms and phases they picked up from video games and such.