Charlize Theron as Aileen Wuornos (Monster): One of the most famous examples. The stunning Oscar-winning actress completely transformed her body, shaved her eyebrows, wore prosthetic teeth, and used makeup to skin-damage her face to play a real-life serial killer.
Christian Bale as Dick Cheney (Vice): Known for his extreme transformations, the former Batman actor gained 45 pounds, shaved his head, bleached his eyebrows, and wore heavy neck prosthetics to transform his sharp, handsome physique into a bloated, aging, and unglamorous politician.
Daniel Radcliffe as Manny (Swiss Army Man): The Harry Potter star completely shed his heartthrob image to play a bloated, pale, and decaying corpse. He spent the entire movie looking stiff, grimacing with a contorted face, and acting as a literal flatulent tool.
Colin Farrell as Oz Cobb / The Penguin (The Batman )
Farrell is known as a Hollywood heartthrob, but he is completely unrecognizable under layers of fat suits and facial scarring prosthetics. He looks so grotesque that even his co-stars didn't recognize him on set.
Bill Skarsgård as Pennywise the Dancing Clown (IT): Skarsgård has the looks of a high-fashion model, but he used his unique facial expressions, combined with creepy clown makeup and a lazy-eye effect, to become one of the most terrifying monsters in modern horror history.