A peacock's tail is a flourish, something that adds to the whole without detracting.
A cocktail combines spirits with other flavors to make them something else.
I don't really drink cocktails, but thr antiquated term makes sense in a particular context.
Now looking it up, apparently the origin of the term isn't actually known and my interpretation isn't even in the running, but I'm saving this anyway because it's amusing.
I was one of the best players in the world while it lasted.
Simple little game, you're a ball and you throw yourself at stars. The more you hit in a row without missing, the better your combo and score.
Essentially pong, but you play the ball, and it's on a landscape rather than somewhere you fall off and die.
I made a few levels for it.
Another was Triptych, which my friends and I called jelly tetris. Imagine tetris but the bits are springy and bounce a bit. It was a blast. Both were commercial games available on Linux at the time, early 2000s.
It was an old dial-up multi user system that charged monthly fees. Once the internet became popular, Compuserve connected, but they predate the commercial home internet.