KEL TU 009 is a comic published in 2013 on tumblr by Kelly Green.
It's a picture of Phineas from the waist up. Phineas is looking up with a genial smile, holding his hat down, allowing us to see a tuft of curly hair on top of his bare skull.
“Just to update (artwork’s been slow the past couple of weeks, sorry), here’s a quick Phineas that I drew when the thought of giving him a hair tuft on the top of his head randomly occurred to me. I dunno, I liked the way it looked in my head.”