A mum who purchased a baby shower gift from a charity shop was shocked on finding what was inside the box.
Veronica Alvarez-Rodriguez told the Northwest Florida Daily News that she and her husband stopped by the Goodwill store in Valparaiso, in Florida, on Sunday (local time) as they were heading to a friend's baby shower.
She found a Baby Einstein's bouncer that was unopened and appeared to be brand new for about NZ$14.
"It was like the perfect gift for the baby shower," Alvarez-Rodriguez said.
However, Alvarez-Rodriguez said the party was in hysterics on opening the gift.
The mum said the father of the unborn baby yelled out, "You guys got me a gun!"
Inside the box sat a semi-automatic rifle.
While some of the guests laughed, Alvarez-Rodriguez said she and her husband were shocked. They called the Crestview Police Department.
Officers came to the party and checked the couple's identifications to make sure they weren't convicted felons, police spokesman Major Andrew Schneider said.
The responding officer initially allowed the father-to-be to keep the gun, which is a Mossberg 715T semi-automatic rifle.
On Monday, police asked him to turn it over to the department.
The incident remains under investigation. There were no details on how the gun got into the box, which appeared unopened.
An employee at the charity store said she couldn't comment.