Post Malone should consider hopping on the Travel Channel's payroll as a ghost hunter if he gets tired of music, 'cause he's got the gift ... so says Zak Bagans.
The "Ghost Adventures" host tells TMZ ... Post recently joined him for an episode that's set to air later this week -- and he says the rapper's a natural at the craft.
Zak says he asked Post to do the guest spot last year, and they taped it in November at a haunted slaughterhouse in Tuscon. He gives props to Post -- a longtime 'GA' fan -- for taking the assignment seriously, and handling it like a pro.
The only possible exception came when Post said he felt a pair of hands wrap around his neck ... and completely freaked.
Still, Zak says the rapper didn't back down and they're planning to have him back, because his episode, which airs Saturday, went so well.