Old Gal Dee Dee is Dee Dee's elderly future self from the episode "Bygone Errors". She is much less spry and agile than her younger self and needs the aid of a walker to get about.
In the far off future of Dextopia, Old Man Dexter spends his time as the wise ruler of the world sleeping on his rocking chair while still living with his big sister Dee Dee. Dee Dee continues to pester Dexter even in their golden years and Dexter still maintains his "sister alert" warning system. During one of their interactions, they spent their time telling stories of their youth (although poorly remembered) with Dee Dee occasionally correcting or worsening Dexter's memory. In the end, Dexter grew too tired and fell asleep and his still loving sister put him to sleep on his rocking chair and gave him a blanket before leaving the room.
- Bygone Errors