She looks similar to Grandma SquarePants, but with the same dark green abrasive side that SpongeBob was using.
Role in episode
After seeing what SpongeBob's abrasive side has done to him after asking him to walk her across the road, she gets one of her own.
She appears at the end of the episode when SpongeBob goes to her house to apologize for his rudeness. He then asks if he can have some of her cocoa, and she tells him to make his own since she is busy. This rudeness is the effect of the abrasive side.