Mattison "Mattie" Gargis is a teenaged female girl who is Collin's BFF since she was only one and Collin was since he was three. She has a very close friendship with Collin.
This cute girl is Collin's Childhood best friend. She is extremely sweet, and her miniskirt can attract some Fingers. Be careful, she may be sweet and extremely sensitive, but mess with her friends in front of her, she is your problem.
- In a early concept of the CTSB 3D, in a 2000 date after the moderns were revealed, Mattie was drawn and appeared to be wearing a extremely different outfit, and (despite having her hairstyle and haircolor) her hair was a a little longer. Her outfit consisted of a plaid camisole, a long denim skirt with pink patches that starts at her calf of the skirt, leggings and short boots. Her outfit from the 30 Years comic are based off that, except its a little bit shorter, no longer has leggings.
- She was so popular in the entire franchise that Spin Master in 2017 created a toyline centered on Mattie on different outfits and different styles, being called Mattie.