The couch gags in opening credits of 'The Simpsons' don't always have to be considered part of the show's continuity, but I think this special presentation could be seen as a legitimate prequel.
Hey, anything goes in the Tooniverse!
And it's special because the concept was dreamed up by noted animator Bill Plympton. And even though his artistic style is radically different from that of Matt Groening, they're both part of the same TV dimension. (Those differences may be seen by us, but not by the inhabitants of the Tooniverse.)