Unusual occurrences are unfolding on the set of “Evil Genius.”

On Monday, David Harbour was spotted looking completely transformed while shooting scenes for his upcoming thriller in New Jersey.

The 50-year-old actor donned a fat suit on the Woodbridge set, which he paired with a blue button-down shirt, overalls, and a tan jacket for his role.

Harbour also sported gray hair, a beard, and glasses to complete his look.

In the Courteney Cox-directed film, which draws inspiration from actual events in 2003, Harbour takes on the role of Brian Wells, infamously known as the “Pizza Bomber,” who committed a bank heist with a bomb strapped around his neck.

The project, co-produced by Jason Bateman, also stars Patricia Arquette.

Harbour, notably, has drastically altered his appearance for roles before.

The Emmy nominee lost 80 pounds to play Jim Hopper Jr. on Season 4 of “Strangers Things” in 2022, going from 270 to 190.

He then had his face filled out with prosthetics during flashback scenes.

Harbour’s weight loss wasn’t “anything more serious” than cutting calories through intermittent fasting, he told GQ that summer.

“We would do, like, six-hour windows,” he explained in July 2022. “And, like, two days a week I would do 24-hour fasts because I started to get more and more intense.”

The Golden Globe nominee also made his diet “cleaner and cleaner” by consuming “a lot more vegetables and less sugar.”

In terms of workouts, Harbour did Pilates, weight training and “a lot of running.”

He subsequently “gained it all back” to play Santa Claus in “Violent Night” in December 2022.

Harbour vowed to the outlet that he would “never again” undergo such an extreme transformation due to “prosthetics [being] too good” of an option.

The Tony nominee has, meanwhile, been making headlines regarding his tumultuous personal life in recent weeks.

Not only did Harbour’s estranged wife, Lily Allen, appear to accuse him of cheating in her scathing “West End Girl” album in October, but reports also surfaced last month that “Stranger Things” co-star Millie Bobby Brown filed a bullying and harassment complaint against him.

Harbour and Brown, 21, put on a united front at the Netflix show’s Season 5 premiere last week — but a body language expert dubbed their camaraderie “overkill.”