He is noted for being the first computer-generated Muppet and probably the first digital puppet created by any company.
The character of Waldo is best described as a cross between a bug and a seal, with random elements of either thrown in. He flies and hovers in his scenes. His first name is a reference to a waldo--a device used by puppeteers to remotely control a puppet. His middle initial likely stands for "Computer", as in "Waldo Computer Graphic".
Although he appeared as a computer-generated image, Waldo was not "animated" in the usual sense, but performed live; his image was generated in real time in synchrony with a physical Waldo-puppet connected to the computer and controlled by a puppeteer, with the image then being composited using bluescreen technology onto the scene Waldo was part of. Since the Muppets began on television, it has always been a standard technique for Muppeteers to perform by watching the characters on a monitor screen rather than by watching the puppet itself, so this arrangement required little adjustment either for the puppeteer performing Waldo or for the puppeteers performing the characters he interacted with. Since Waldo is a computer graphic, he has the ability to change his shape and form at will.