A Wisconsin mom who experienced every parent’s worst nightmare relived the horror of discovering a babysitter had returned her 2-month-old dead in a car seat.

Heather Gardner, of Wausau, said her son Benson’s caretaker, Marissa Tiesort, handed over his lifeless body and pretended he was still alive, news station WAOW reported.

Tiesort, 28, is accused of bundling the dead baby in a snowsuit, pulling his cap over his eyes and placing him in a car seat. Authorities believe the 2-month-old likely was dead for two hours when he returned from her care.

“When we got to the laundromat, I started unpacking Benson and I was like why are his lips like, they were like stuck together, so I was like, ’Oh my God’ and I unzipped his snowsuit and took him out and he’s like hard,” Benson’s mom said of the Oct. 18 incident.

Tiesort, a pregnant mom of five, was charged last month with first-degree intentional homicide in connection to the baby boy’s death.

She later confessed she was aware the baby wasn’t alive when she returned him — but claimed she didn’t kill the infant, according to court records.

Investigators said Tiesort also admitted to going to McDonald’s with her boyfriend and the baby’s body.

An autopsy revealed the boy died of blunt force head injuries.

The Wausau Police Department said the death is still under investigation.

“We are confident that we will get justice for Benson when that is concluded,” Wausau Police Detective Jennifer Holz told the news station.