By Cherise Leclerc

DERRY, N.H. (WMUR) -- A young girl from Derry is set to have a magical Halloween.

Riley Marquis, 5, is in a wheelchair, and her family sometimes has trouble putting a costume together for her.

Thanks for an Oregon-based nonprofit organization, she and her chair will have the costume of her dreams this year.

Volunteers from Magic Wheelchair presented Riley with a custom pink Minnie Mouse car, designed to fit over her wheelchair, on Wednesday.

"She's got her own car now,” said Amy Marquis, Riley’s mother.

Magic Wheelchair was started by a father who has children who use wheelchairs. His idea has inspired people across the country to volunteer their time and talent for the nonprofit.

"It's, like, two months of just working really hard, knowing that that's the outcome,” said Bonnie Regan, who built the car for Riley.

Over those two months, Regan used insulation foam and other materials to transform the chair into the custom car.

It’s a welcome respite for Riley and her family, who have been through a lot in her young life.

"Riley has a terminal illness called Leigh's disease,” Amy Marquis said. “It's a neurological disease."

Diagnosed when she was 13 months old, Riley has surpassed the odds.

"We could be going through the worst things with our jobs and our home and everything, but she's going through the worst thing and she can still have a smile on her face,” Amy Marquis said.

Riley’s friend, Silas Brown, another Derry child who is wheelchair-bound, will also be getting his very own custom wheelchair costume from Magic Wheelchair on Saturday.

"Over a week's worth of time, we asked him which costume he wanted to be in, and he ended up picking Max from ‘Where the Wild Things Are,’” said Melly Brown, Silas’ mother.

Both kids will be trick-or-treating in style.

"It's awesome because it doesn't make the wheelchair like a tool,” said Jason Marquis, Riley’s father. “It's actually something that's fun for her to do."