There's nobody like Paul Williams. He's written hits for The Carpenters AND Kermit The Frog (and many, many others over several decades). He was in a Sunshine-Pop band called The Holy Mackerel with his brother Mentor (who later wrote Drift Away for Dobie Gray). He played a kid in The Loved One when he was already in his mid-20's. He played an Ape in Planet of the Apes. He wrote the songs and appeared in Phantom of the Paradise. I could go on and on.
Now he's the subject on a new documentary. Check out the trailer here. I'm looking forward to it.