Cookie was adopted by Kentin in Episode 24, thus officially introducing him to the series. Your Candy meets him in the park where Kentin introduces him to her as long as your Candy didn't go buy cookies first and heads straight to the park.
Not much is known to date about Cookie prior to his adoption. He might have been a stray puppy before he was brought to the pet shop, as most animals there have been rescued.
Cookie is a beautiful German Shepherd puppy. He has glistening dark brown eyes and pointed ears. His fur pattern is of a caramel undertone and dark brown detailing. He appears to have a medium black saddle pattern and dark black mask that German Shepherds usually have. He has a long shaggy tail and is long haired.
According to Kentin, Cookie is very playful, loving, and tends to get excited very easily. However, since he's still just a puppy, he also causes messes in the house.
Even though Cookie can cause trouble, Kentin still loves him and shows a lot of pride in his puppy. Cookie also has unconditional love for Kentin.
If your Candy goes to the pet shop with Kentin, she later meets Cookie in the park. She is happy to see him in Kentin's care, noting that Kentin will surely make a great dog owner.
Guy allows him to adopt a dog, saying it would be good for him to take on more responsibilities. He isn't too happy when Cookie makes a mess in the house, though. Kentin says Cookie brought a better ambiance to his home, and that it's much happier since he's there.