I'd estimate about 20 years ago I saw a British comedian called Ross Noble who did this. He almost acts like he's got some form of ADHD where he is permanently distractible, will switch topics mid-sentence because something else gets his attention. Someone came in late, so he asked them what took them so long. Someone wearing a hat catches his eye and he makes a comment and goes off on some tangent. Those tangents can be minutes long. Eventually he always goes "right, now where was I?" and resumes the scripted/rehearsed part of his show.
And then... in the final minute or so of the show all of those seemingly random distractions and tangents come together to tie up the various stories and jokes he'd been telling! Decades later when I think about it it still blows my mind. They can't have been random at all. I've no idea if the various distractions were plants, or maybe they never existed at all and everyone in the audience just thought we were all too far away to hear whoever he was talking to? It was such a flawless execution though, only heightened by the fact he'd convinced you he was a rambling unfocussed mess for most of the night.
And then... in the final minute or so of the show all of those seemingly random distractions and tangents come together to tie up the various stories and jokes he'd been telling! Decades later when I think about it it still blows my mind. They can't have been random at all. I've no idea if the various distractions were plants, or maybe they never existed at all and everyone in the audience just thought we were all too far away to hear whoever he was talking to? It was such a flawless execution though, only heightened by the fact he'd convinced you he was a rambling unfocussed mess for most of the night.