Several dozen cardiac arrest survivors are recalling eerily similar and bizarre experiences while dying -- and an author, who herself clinically died, is revealing her own encounter with the other side.
Author Mary Curran Hackett joined us Friday on "TMZ Live," recalling 1 of many cardiac arrests she says she's suffered over the years ... this one in 2004, when she flatlined in a hospital, and had a literal out-of-body experience.
During the ordeal, Mary says she felt calm while essentially being tapped into everything happening around her body -- from feeling the anxiety rising in her nurses' blood pressure, to seeing doctors leave another room in the hospital to come to hers.
According to Mary, she was fully aware during the minutes that her heart stopped but was seeing everything from a new perspective ... adding she felt at peace before being sucked back into her body.
Mary believes there are loads of unanswered questions about this fascinating and terrifying moment in people's lives, which is why she's working with Dr. Sam Parnia on his study of cardiac arrest survivors.
She says he's compiling their experiences in an upcoming book called "Lucid Dying" ... which sounds like a fascinating and revolutionary probe of the unknown -- what exactly happens to us when we die.