Last night, zombies, princesses, pirates, cowboys and an 85-pound Burmese python all had a chance to mingle among the dinosaurs in the darkened halls of the Yale Peabody Museum of Natural History.

Museum staff closed down the Peabody to the public during its regular hours of operation on Thursday in order to transform the first floor for the museum’s inaugural Haunted Crawl and Costume Ball. The event included a “tour of terror,” the chance to touch live snakes, a costume contest, a live DJ and food. Attended by over 500 guests, the occasion marks one of the first ever 18-and-over only events at the Peabody.

“I’m very excited for an event that gets adults in the museum having fun and getting more accustomed with the collections,” Peabody Head of Education and Public Outreach David Heiser said. He added that the event is the perfect opportunity for undergraduates to mingle with the greater New Haven community.

In past years, the Peabody hosted public Halloween events geared toward families. Event themes included “the natural history of witches and wizards” and “creepy crawlies.” But last year, the museum staff felt they were overloaded with public events and did not host a Halloween happening, Heiser said. However, this year, the staff, missing the Halloween preparations, decided to create a scary event specifically for adults.

For the costume contest, prizes were awarded in two categories — individual and group costumes. Peabody Director David Skelly, Business Manager Susan Castaldi and Director of Public Programs Richard Kissel functioned as the evening’s judges. Prior to the competition, Kissel said he looked forward to the creativity and diversity of costumes among attendees. Winners received gift certificates to Modern Apizza and BAR.

The haunted crawl included museum staff dressed as mummies, disfigured corpses and mad scientists, all doing their best to spook attendees.

“I was actually scared during the haunted house,” Juliet Ryan ’16 said. “But I was in love with the ’70s music vibe.”

Ryan, dressed as Blues Clues, also had the chance to touch live reptiles and hold her first “legless lizard,” brought by a local reptile keeper to the Peabody. The keeper also brought anacondas, corn snakes and a Burmese python that weighed in at 85 pounds and measured over 13 feet long. Ryan said she “cried a little” when she touched it.

The walk also included a “mad scientist room” which featured parts of the Peabody collection not usually on display. Castaldi said the staff took this room as an educational opportunity to allow visitors to view more specimens — but in a very lighthearted way.

“We have a wonderful assortment of creepy and crawly from the collections, including exotic looking worms, squids, octopi and some wonderfully grotesque creatures in jars,” Kissel said. “We want to set the mood of Halloween.”

Kissel also handed out special treats, including chocolate-covered ants and crickets, for those visitors who were brave enough to walk — or run — through the haunted crawl.

Susan Castaldi said that between Monday and Wednesday afternoon, over 300 tickets were sold. The event sold out at 520 tickets, 67 percent of which were purchased by Yale graduate and undergraduate students, 21 percent by faculty and staff and 12 percent by the general public.

Standing outside the packed museum, Andres Valdivieso ’16 waited as his friend experienced the haunted crawl without him. Valdivieso said he had told all of his friends to buy tickets for the event, but he forgot to buy his own and was surprised that the event sold out.

Castaldi said the museum plans to continue this event in the future. Staff even hope to have two similar adult-only events in the spring, she added.

Tickets cost $5 for Yale students.