The Man Who Can't Breathe, also known as the Wheezing Demon is a very dangerous and malevolent entity from The Further and is the main antagonist of Insidious Chapter 3.
Insidious: Chapter 3
In the movie, He heard Quinn's voice as she tried to contact her dead mother. He then began to terrorize Quinn. He later brings her to The Further, feeding on her soul. Elise, Specs, Tucker, and Quinn's father Sean try to stop him and rescue Quinn. The demon is known for possessing his victims, usually forcing them to commit suicide in order to take them away into the darkness forever. He briefly possesses Quinn and tries to make her kill herself with a knife, but Sean, Tucker and Specs are able to restrain Quinn long enough for Elise to arrive and help.
His goal is to drive souls to suicide and keep them in the dark as his "pets". He tries to drive Elise to suicide by pretending to be her husband, Jack, but once the demon (as Jack) asks Elise to kill herself, she knows it isn't her husband and slashes at the demon with a knife. Elise bravely battles the demon and gets Quinn back to her body, but the demon catches Quinn just before she can make it back. In the physical plane, the now returned Elise, and the others join hands with Quinn to mentally support her, in order for her to win this final battle of her and the demon alone.
Lilith, Quinn's mother, makes an appearance thanks to Elise's calls for aid and helps her daughter stand up to the demon. In The Further, Quinn regains her will and quickly rips the breathing mask off of the demon, killing him.
The Wheezing Demon wears a breathing mask and a dirtied, frazzled hospital dress. His skin is rotten and his feet are seemingly covered in a thick layer of tar, which strongly confirms his presence by the black footsteps he leaves.
He is also known to be making wheezing sounds, which explains his other name.
His appearance suggests that he was a man who died of some kind of respiratory illness (hence the breathing mask and the gown).
Much like the other antagonists, The Wheezing Demon is a vicious and corrupted entity that has some control over a part of The Further, specifically The Further version of the apartment complex that the Brenner family lives in. According to Elise, he's a different type of entity, one who thrives in the shadows and enjoys dragging pure souls in there with him, rather than claiming living vessels in order to be alive again.
He is clearly powerful and is very strong, throwing Quinn out of her bed, climbing walls, stomping on the ground making things move and get tossed around in the air, as well as grabbing Elise and throwing her in the air. He also nearly killed Quinn by dragging her out the window.
In the meantime, it is revealed that Quinn isn't his first victim. He may have claimed more than one victim in the past, hence Elise's saying he has resided in the complex for a very long time.
- Elise refers to him as a 'demon'. However, his appearance is somewhat more human compared to the Lipstick-Face Demon, whose appearance is more monstrous. Making it possible that he is in fact a ghost and not a true demon. This could simply be a form of expression on Elise's part.
- The hospital gown and oxygen mask suggest he may have been hospitalised before his death by an illness, possibly respiration-related due to his characteristic wheezing.
- The Wheezing Demon is the only antagonist who has not appeared once in the previous movies and share any connection to the Lambert family.
- The Wheezing Demon is the second entity to fight Elise onscreen; the first is Parker Crane.
- The Wheezing Demon shows caring emotions to Quinn to show he cares.
- The Wheezing Demon is the first demon to go in Elise's house.
- The Whezzing Demon is the only antagonist that goal succeeded.
- Writer/Director Leigh Whannell told casting that he wanted the Wheezing Demon to look like the Sloth victim from Se7en. The same actor, Michael Reid MacKay, was cast for the role.