Weezer Bassist Ex-Wife Jillian Lauren Shriner on 'Ghost Adventures,' First Look

The "Ghost Adventures" episode featuring Weezer bassist Scott Shriner’s ex-wife, Jillian, is about to air ... and TMZ’s got the chilling first look, giving a pretty unsettling peek into her headspace before that wild run-in with cops earlier this year.

Have a look -- Zak Bagans says things took a seriously dark turn after Jillian gifted him serial killer Samuel Little's ashes, along with hand-drawn portraits of his victims that he’d left her in his will after she once wrote a book about him.

Zak says Samuel’s remains were placed inside his Vegas Haunted Museum, alongside Charles Manson’s, and it wasn’t long before strange activity started popping off ... triggering a pretty intense reaction from Jillian.

Jillian says those ashes were literally in her home, and every time she walked into the room, she felt herself folding, sinking deeper into depression.

Remember ... production sources told TMZ Jillian filmed the episode in November last year ... and just months later, in April, she allegedly fired a gun at officers searching for a suspect near her Los Angeles home in an unrelated incident.

Jillian was arrested on suspicion of attempted murder of a peace officer, but prosecutors later downgraded the charges to assault and negligent discharge of a firearm. She avoided jail time -- with a judge granting her diversion due to mental health issues.

We broke the story that Jillian filed to divorce Scott earlier this month after being married for 20 years.