The 10-year-old looks like one too.
A therapist at the Queen Elizabeth II hospital in Halifax has painted the white cast-like mask with the fearsome black, green and white pattern of World Wrestling Entertainment professional wrestler Oscar Gutierrez, also known as Rey Mysterio Jr.
The wrestling mask created by Jen DeGiobbi also has crosshairs in three spots, helping precisely target the waves of flowing radiation that will shrink the boy's brain tumour.
The mask is one of several decorated for patients by therapists at the facility.
The goal is to help patients calmly cope with the treatments, which require them to lie stone still.
"It doesn't just represent a cast, it becomes quite personalized to them," says Deanne Robinson, as she prepares Brandon for his treatment.
"By their choosing something close to their heart I think it makes the whole process a lot easier."
The end goal is pragmatic, she adds.
"We don't want him to be able to look left, right, up, down, anything. It's an effective immobilization technique."
The therapists have also decorated masks with the emblem of super heroes and flowers.
And it seems the power of dress-up can transform the mood and confidence of both adults and children.
"We had a fella here with a tumour who had Philadelphia Flyers put on his cast," she said.
MacKenzie says since the idea for his mask came to him, he's been in frequent telephone contact with Mysterio, and has received an actual wrestling mask used by the wrestler in the ring.
"He (Mysterio) said, 'We're going to do this like a tag team,' and he said, 'I have your back and we're going to do this together,'" he said.
Radiation oncologist Rob Rutledge says he's grateful to the therapists for their concept and the time they've devoted to creating each mask.
He says the treatment goal is to target tumours and avoid damaging healthy tissue, and any method that helps reduce a patient's discomfort over having their head latched down is helpful.
"I recently had a girl who was seven years old go through this treatment and she was in tears the first day she had to do this but the fact she had such a beautiful mask to go back to made the treatment much easier," said the physician.
After his treatment, MacKenzie has another wrestling sticker pasted on his chart— fourteen so far with four more to go until the clinic will ring a bell to announce he's completed the process.
He's still looking forward to coming back from his home in Port Hood, N.S., for the next dose of radiation.
"I feel like Ray Mysterio," he says.