From Monkey Island wiki
Franklin is the name of a guide dog Guybrush finds in the Crossroads. It is suggested Franklin is Galeb's guide dog, though due to Galeb's nature, it's never made too clear. Franklin is found around the graves where souls enter the Crossroads. He helps Guybrush find the spell LeChuck buried there to return to the land of the living, and Guybrush uses him as an ingredient (his "guide") to complete the spell.
Franklin recalls two dogs from Monkey Island 2: LeChuck's Revenge: he finds a particular piece of paper in a huge pile like Guybrush the dog does in the treehouse on Booty Island, and he is credited "as himself" just like Walt.
- Franklin's personal appearance kind of resembles the appearance mostly of a Scottish Terrier dog.