Granny is very old and when she tells stories of her young life sometimes, they can be a bit long, gross, or boring (especially to Jimmy).
Granny is said to be over 60 years old. She has light Gray hair tied into a bun and wears glasses. She bares a strong resemblance to her son, Hugh. She wears a Green long sleeve dress with White lace and Black heels with White stockings.
As a baby she is bald except for a single brown curl on top of her head. She has big brown eyes and one bottom tooth. She wears only a diaper.
In her first appearance in "Granny Baby", Jimmy accidentally turned her into a baby. It was hard to handle her like that considering that she needed her diaper changed and kept crying until it was. The situation continued to worsen until Jimmy got Cindy to change the soiled diaper. When she was a baby, Granny had a pooping and gas problem as she couldn't stop (she is awfully old, so it makes sense that her new young body released all her backed up bowels). Not too long after her dirty diaper was changed, she soiled her diaper again and asked for another diaper change. While she could still talk and use big words, her mind was immature and it made her act like a regular baby. Unfortunately for Jimmy and Cindy, this meant changing her poopy diapers.
It is also revealed in this episode that she normally wears diapers as an adult, which is mentioned just after she has transformed into a baby.
"Send in the Clones"
"Clash of the Cousins"
While not actually appearing, Granny has been mentioned as being in Reno at the time of the party.
- Granny Neutron wasn't the only Nicktoons character Phyllis Diller did the voice for, as she previously voiced Aunt Mitzi on Hey Arnold!
- Granny makes another appearance in Send in the Clones when the perky Jimmy Clone spends time with her in the park but he made her smile so much that her dentures fell out of her mouth and went to his house to complain with the rest of the townspeople.