Brenda Cruz and her family saw the man hanging on to the back of the car as other vehicles nearby began to slow down.
"All of a sudden the kids say, 'There's someone on top of the car on the trunk,' and I'm like, 'What?'" Brenda Cruz said. "I said, 'Let me get my phone and start recording.'"
Her 17-year-old son, Samuel Cruz, said he thought the man was a dummy at first.
The family said the man smashed through the back window to climb into the white car, which was driven by a woman and had a child inside.
"Whenever he lifted his hand to smash the glass open it looked like it was something sharp," Samuel Cruz said. "I'm really worried because I just hope she's OK, you know, with her kid."
North Carolina State Troopers were investigating the incident, but haven't been able to track down the vehicle or people involved. They said ultimately the driver was responsible for the incident.