Scooby Doo 2: Monsters Unleashed has been my favorite childhood movie ever since I first saw it. But while the plot and all for fun, the Tar Monster is the main reason and is also what made me develop slime as a fetish. I like him so much I decided to make a character that is basically a copy of the Tar Monster. Same general powers, same general personality with some slight alterations.
(Also, I'm super proud of this art I made.)

Gender: Male
Age: Adult
Height: Variable
Weight: N/A
Appearance: The Tar Monster is a creature that seems to be made almost entirely out of constantly-flowing and dripping tar. He has a single large eyeball with a blue iris, and a wide mouth filled with sharp-looking metallic teeth. The teeth on his upper jaw are larger than the teeth on his lower jaw. He has green breath. Out the sides of his body, he has two large arms, each having a hand with three fingers. He seems to possess a pair of large and somewhat short legs, but they are hard to make out past the tar constantly flowing down his body.
Likes: Trapping humans, wrapping them in tar, making them helpless, devouring them.
Dislikes: Boring humans, monsters who wish to befriend humans.

Powers
Tar Body - The Tar Monster's body is made completely out of a seemingly infinite mass of a thick black slime called tar, with the only exception seeming to be the large eyeball. He can morph his tarry body into any shape he wants, some common examples being a puddle, tendrils, a wave, a massive hand, or even just enlarging himself. He also appears to be able to transport himself between puddles of his tar at will.
Breath - The Tar Monster possesses a green breath that is slightly smelly. When breathed out normally, it doesn't affect a person much. However, when released in bigger doses, it can daze or completely knock out a person for a short while.
Nightmare Realm - The Tar Monster possesses his own realm to take people to in order to terrorize them. He can design this realm however he likes.

Personality: The Tar Monster is an evil monster that loves nothing more than terrorizing humans and trapping them helpless in his tarry body. He almost constantly wears an evil grin on his face, showing his sharp-looking teeth and glaring at his prey with his large eye. Despite being called the Tar Monster, the substance he's made of is much unlike the human world tar and is more accurately just a thick black slime, though it is still referred to as tar.

When abducting someone and bringing them to his realm, the Tar Monster uses his powerful green breath to knock them out and keep them unconscious while he pulls them in. The Tar Monster's realm always takes the form of an empty, walled-off city at night, and when his prey awakens, they'll find themselves alone there. The Tar Monster's hunting method is usually to set tar puddle traps and lie in wait. Then when someone has stepped in, he'll use tar tendrils to enwrap the victims legs while he forms himself up from the puddle, and then grab them in his hands or arms. He may deviate away from this method a bit sometimes, especially when dealing with multiple prey, in which case he may show himself and just spread his tar and entrap them all at once. The Tar Monster relishes in his prey's fear and utter helplessness as he slowly wraps them up in his tar, often laughing evilly and taunting them in his deep voice as he watches them. He never covers his prey's nose, ears, or eyes, preferring to keep them conscious and able to see and hear him as he teases and torments them. After he has spent a good long while teasing them and engulfing them in tar, he swallows them whole and traps them in his tarry chamber of a belly.

Despite the Tar Monster's evil personality, he is not all bad. For one thing, he never seems to actually hurt his prey. Even when he devours them, he never lets them drown in his tar and he never squeezes them too tightly in his hands. Additionally, while he may keep a person for longer than just a single night, he'll eventually let them go if he becomes bored of them. Though instead of getting bored, another possibility is he'll let someone go to come back and terrorize them again. Nick is someone the Tar Monster frequently abducts and lets go once he's had his fun. While the Tar Monster prefers fear from his prey, he may be amused by a person developing a bit of a fondness for his domination and submitting to his gooey clutches. However, he quickly becomes very bored of overly willing prey who don't offer any resistance at all. The Tar Monster is completely against monsters such as MUB befriending humans, thinking all humans are prey, playthings, and pets.