He looks mostly like the normal Patrick, but is tiny, with completely green shorts, and doesn't have any freckles.
He also babbles in unintelligible gibberish rather than real speech.
Role in episode
When SpongeBob and Patrick are sad that they have to leave each other, they decide that they cut out parts of their body to make mini versions of themselves, and SpongeBob gets the Patrick mini. While he's with SpongeBob, he is initially treated with kindness by the latter but repeatedly gets tortured, soon after. He and Mini SpongeBob (Fun-Sized Friends) break free and decide to torture SpongeBob and Patrick so they can get a taste of their own medicine. The Patrick and SpongeBob mini's try to have a good living in SpongeBob's Pineapple, but their too small, so the big SpongeBob and Patrick give the Patrick and SpongeBob mini their own house.
Afterward, they feel something is missing and soon Squidward finds himself in the sand while the Patrick and SpongeBob minis are playing. He is annoyed at the pair abducting him and they hug his nose as an apology.