Sid Phillips
Sid Phillips is a mischievous and somewhat troubled 11-year-old skateboarder with a rebellious attitude. He wears metal braces and takes pleasure in tormenting his younger sister, Hannah, by confiscating her toys and subjecting them to unsettling experiments.
He enjoys swapping their heads or conducting "surgical" procedures on them. Plus, Sid has a penchant for destroying toys through various means such as explosions, burning, or enacting "mad doctor" scenarios.
While Sid Phillips is not a true villain - since he was unaware of the toys' consciousness when he mistreated them - the perspective of the film, being from the toys' point of view, positions him as an antagonist. Not to mention, his disturbing tendencies towards mutilating and destroying toys bear resemblance to the actions of a budding sociopath who inflicts harm on animals.
It was only after Woody and the other toys frightened Sid to the point of terror that he vowed to never abuse toys again, developing a clear fear of them - which his sister Hannah took advantage of.
Movie: Toy Story
Release: 1995