CHARLOTTE—People working in Duke Energy Center were treated to a Halloween trick Friday.        

The window cleaning crew dressed up in their ghastliest outfits; one was a werewolf, the other, Frankenstein’s Monster.

Diane Black, who’s worked in Charlotte for 25 years, says she’s never seen anything like it, and she loved the surprise.

“No, you don't expect that when you're working. And you look up and see that!” she said.

The crew is also known for dressing up as superheroes to clean regional children's hospitals.