Mabel Syrup is the author of Commander Coriander Salamander and 'Er Singlehander Bellylander, the sequel to Hamster Huey and the Gooey Kablooie. She was mentioned in a single weekday comic where Calvin clamors for his father to buy him the sequel to Hamster Huey And the Gooey Kablooie.
It is unknown whether Syrup also wrote the original book, but it is somewhat implied as Calvin referred to Commander Coriander Salamander and 'er Singlehander Bellylander as "Mabel Syrup's sequel to Hamster Huey and the Gooey Kablooie".
Syrup's name is a play on the noun "maple syrup", a viscous, sweet condiment.