What was the name of the pen that not only made music when Mr. Cosby wrote with it but also came to life?

Mortimer Ichibod Marker

What was the name of the pen that not only made music when Mr. Cosby wrote with it but also came to life?
The name of the marker was "Mortimer Icabod" Marker... Lol, Look up the show on Youtube, I found it and many others from my childhood.