Actually, it's from the pilot "House of Bloos". There's a little stuffed animal that looks an aweful lot like Ed on Mac's floor. Kind of odd if you ask me, being the very first episode, and Mac hadn't even met Ed (or the rest of the friends) yet. Some speculation before "Good Wilt Hunting" wondered if maybe Ed was Mac's mom's friend when she was little, that may explain why the stuffed "Ed" was there. She could have made it for him herself. But after "GWH", we see that that's not the case. I guess it was just a fun little thing the story board writers threw in there.
