From Wikipedia...
A furry green creature with a cylindrical beak containing a tongue that sticks out, he was created by Harrison/Erickson of New York City (now known as Acme Mascots), who have had ties with Jim Henson's Muppets and the team's marketing and promotions department during the winter after the 1977 season by a young executive named Dennis Lehman, who thought that the team needed a mascot similar to The San Diego Chicken. The character is named for the fanatical fans of the team after an incident during the third game of the 1977 National League Championship Series played at Philadelphia's Veterans Stadium, in which fans drove Los Angeles Dodgers pitcher Burt Hooton into losing his composure (he was removed from the game, but the Dodgers went on to win the game, and ultimately, the series).
That thing has been around since the 70s. I think it's not really supposed to be anything. Think Muppets.
