Mike

Life goes on as usual in the small town of Hawkins, but not for Mike Wheeler, who has taken guardianship of his best friend, Will Byers, to the point of absolute absurdity. Mike now operates exclusively in "90s action movie bodyguard mode," constantly suspecting that either the Demogorgon or, worse, a bad grade in math awaits Will around every corner.
The plot revolves around a high school prom. Mike is convinced the event is a trap set by the Upside Down. While Will is simply trying to choose a bow tie, Mike constructs a protective suit around him out of pizza boxes and duct tape, claiming it's "armor against social upheaval." Every time someone approaches Will simply to say hello, Mike performs a dramatic somersault over his shoulder and stands between them, shouting pompous phrases about loyalty and honor.
Will, the embodiment of melancholy calm, tries to explain to his friend that the Mind Flayer is unlikely to be hiding in the punch, but Mike is too busy interrogating the school DJ. The absurdity reaches its peak when Mike intercepts a "suspicious" note addressed to Will, thinking it's a monster cipher, when in fact it's simply an invitation to a movie from a classmate.
In the finale, Mike accidentally knocks down all the decorations in the gym while trying to "save" Will from a falling balloon. As Will stands in the center of the tangled garlands, Mike pompously announces that the perimeter is clear. Will merely sighs, adjusts his bowl-cut hair, and offers Mike a sandwich, finally admitting that with such a hyperactive protector, no evil in the world truly threatens him—it simply won't get past Mike's line of complaints.