Dennis is usually represented as a coyote, but he is also sometimes shown as an R1/1995 style limbless humanoid, a dragon, and an Eevee.
Dennis has light yellowish peach skin and brown hair with two black tips. His clothing consists of a green t-shirt with a "X3" symbol in the center, light blue pants, and red sneakers with blue highlights.
In his coyote form, Dennis's fur is the same color as his hair, and wears only his shirt.
In 2017, Dennis's look was updated. His shirt is now slightly more detailed (in both forms) with dark green trim. Dennis also has a belt in his limbless form. His coyote form now has black ear tips, tan markings on his belly, and wears open-toed versions of his shoes.
He is very friendly, and likes to be around his friends. He is warmhearted and sometimes childish, but can act mature and takes control of the situation, although sometimes the situation is out of his hands. This doesn’t stop him from being a good leader though.
Dennis currently lives in Toontown Central (the same place where Flippy Doggenbottom runs for mayor), yet he goes on countless adventures with his teammates; Luna the Dragon, Lenny Kangaroo, Molly Kangaroo, Augie Dingo, Maralyn Koopa and Kyle the Dog. Dennis is also great friends with Rayman (character), Bubsy Bobcat, Max Goof, Parappa, Blinky Bill, Flap Platypus, Shifty Dingo, and many others.
- Dennis is an original character created by JustinandDennis.
- In ToonWorld, Dennis is voiced by Jaleel White.
- Dennis is one of the two main mascots of JustinandDennis's profile.