WEEEEEELL what I had always assumed was that this came from the first Planet in Peril that I have yet to completely watch bawww, and the fact that he apparently was a bit fixated on the turtles there. See also that one macro where he is talking to Jeff and holding this seething and straining turtle in his one hand XDD.

THAT IS WHAT I HAD FIGURED, BUT I AM UP TO BEING SCHOOLED BY PEOPLE MORE VERSED IN ANDY COOP THAN ME :D;;