It was to bring smiles to sick kids.
Spider-Man, Wonder Woman, Superman, Batman and more showed up in Spaulding Rehab during a visit open to all ages that was coordinated by a former patient.
The patients, too, dressed up as their favorite masked protectors of the innocent, making for a heartwarming scene.
A young boy named Aiden visiting his uncle said that the patients were the true superheroes, but his Uncle Paul was quick to praise the cosplayers.
"I am no superhero. They are," Paul Dolimpio told WCVB. "They have so much talent and they go and share that with other people. That is all that matters."
Read more about this story from WCVB.