Girly TeenGirl is a female teen sponge who had just moved to Bikini Bottom from Farawayville in the episode The Slumber Party. Pearl and her friends all think she is SpongeBob in disguise, so they throw tomatoes at her. She looks a lot like SpongeBob but it is shown that she isn't SpongeBob because as she is running away, SpongeBob and Mr. Krabs immediately drive up and have no idea who she is.
- Ironically, though she looks a lot like SpongeBob, SpongeBob thinks that she is ugly.
- Girly TeenGirl's hometown is Farawayville.
- A similar joke was also used in the episode No Weenies Allowed as Reg mistook The Drifter for SpongeBob.
- She has lips and a voice that sounds like she has a bad cold.
- Pearl thinks Girly TeenGirl is SpongeBob in disguise, sent by Mr. Krabs to spy on her.
- Girly TeenGirl has the same eyelashes as him.
- When Girly TeenGirl says "I'm umm... Girly TeenGirl", it looks like she's hesitating to think a name up. This made Pearl think it was SpongeBob.
- She is voiced by Tom Kenny, the same person who voices SpongeBob SquarePants, because her scream sounded exactly like SpongeBob's.
- Because Pearl thinks that she is SpongeBob, this means that Pearl does not know who Girly TeenGirl is. So it is unknown why Girly TeenGirl showed up at Pearl's slumber party, unless perhaps one of Pearl's friends invited her.
- "I'm so moving back to FarawayVille!"
- "My name is, um...Girly TeenGirl! And I moved here from, uh...Farawayville.
--This last quote hints to Pearl and viewers that it is obviously SpongeBob, making up a name on the spot. However, she is, of course, a normal sponge who has nothing to do with Mr. Krabs having SpongeBob spying on Pearl.