She has red eyes and wears a long dark pink dress and light green slippers. Her skin color is similar to Squidward's, only slightly darker and with wrinkles. She has gold earrings and white hair.
In "Chum Fricassee," Grandma Tentacles was shown to be extremely abusive, antagonistic, and hostile towards her grandson Squidward, such as frequently stomping on his foot with her walker and telling the customers to destroy the Chum Bucket in revenge. On the other hand, Squidward had cooked her recipe incorrectly, thus giving the customers severe stomach problems, so her anger was justified. She even stated that she hoped he learnt his lesson after ruining her famous recipe, which proved she only wanted him not to try it again.
Despite her abusive behavior towards Squidward in "Chum Fricassee," Squidward mentions in "The Two Faces of Squidward" that she gave him homemade soap, showing that she does love and care for him and her abusive behavior is only to discipline him for his actions.
Grandma Tentacles was born from unknown octopuses.
Years later, she married an octopus and gave birth to Jeff Tentacles, who would become the father of Squidward Tentacles.
She also gave birth to an unknown Mr. Tentacles, who would become the father of Squidward's cousin.
At some point, she created a recipe for Fricassee. When Squidward was young, she taught him about her famous recipes.
Role in series
Grandma Tentacles is mentioned in many episodes. She makes her first physical appearance in "Chum Fricassee" where she storms into the Chum Bucket furious at her grandson for cooking her recipe wrong. After she smashes Squidward's foot several times using her walker, her grandson tries to frame Plankton for serving the undercooked chum. Plankton puts the blame back at Squidward by reminding him that he told him that he didn't care if the food was ready or not.
Squidward admits that he served the undercooked chum only for his grandmother to smash his foot again, warning him that if the chum is not properly cooked, it will cause severe upset stomach. The customers are enraged when they learn that they have eaten undercooked chum and destroy the Chum Bucket in retaliation.
She tells her grandson that she hopes that he learned his lesson about misusing her recipe and stomps on his foot again as punishment for his actions.