She is a light pink-colored worm with light yellow eyes and black pupils. She has a darker shade of pink under her body, and has short light-red legs similar to those of an ant. Little hairs can be seen sprouting out at certain places of her body. She resembles a dog just like the other worms in the show, due to her barking and fighting with Gary, who is the equivalent of a cat.
At first, she seems tame and docile, but from the way she acted, Mrs. Wormsley gets quite angry with Gary, resulting in a fight with each other. This is because she and Gary hate each other since they fight like cats and dogs, as they are the underwater equivalents. Gary once again fights Mrs. Wormsley and wins the duel, abandoning her newborn litter and most likely making her leave town.
Originally, SpongeBob called the worm Mr. Wormsley, thinking she was a male. Soon, though, he discovered she was a female when she gave birth. Mrs. Wormsley had five small babies, all of which were sold at the end of the episode.