Picked out your Halloween costume yet? If you live in the Denver area, add a pair of running shoes to your outfit and get ready to Scram.

Sponsored by the Scream Agency, the first annual Scream Scram is a 5K run/walk—in costume—to be held in Washington Park on Oct. 27.

The Denver shop devised the race to encourage people to engage in outdoor activities and to raise money for the National Multiple Sclerosis Society.

“I’ve been running for more than 20 years,” said Lora Ledermann, Scream founder and creative director. “I’ve always wanted to hold a race that offers a creative twist. Plus, it helps build our brand, and it’s for a good cause.”

Scream created the funky race-entry forms and posters and is distributing them to local running clubs and health stores.

The shop is working with its outdoor clients—including backpack maker Mountainsmith and clothing company Horny Toad Active Wear—to donate prizes to the top runners and walkers.

Ledermann hopes to raise $2,000-3,000. “It’s a chance to dress up and be outdoors,” she said. “We’re going to have fun with the race.”