John Cena's decision to participate in a Nickelodeon hidden-camera show helped an 8-year-old kid SAVE HIS BABY SISTER FROM CHOKING!!!
Seriously -- it's an unbelievable story!
8-year-old Jaxson Demsey was on a family outing in Hazleton, Pennsylvania over the weekend -- when he noticed his 20-month old sister was having trouble breathings.
Fortunately for the Demsey family, Jaxson had watched an episode of the Nickelodeon show, "The Substitute" ... which featured a cameo from WWE superstar John Cena.