This baby delivery was no joke.

A Tennessee doctor was dressed up as the Joker for Halloween, when his trick-or-treating plans suddenly changed. There was a baby to deliver, so the doctor had to rush to the hospital. When he got there, the delirious parents-to-be wanted him to keep his costume on — so he happily obliged.

"Dr. Joker" delivered a healthy baby girl. She might be scarred for life — or she'll just grow up to really love a good superhero movie.