At what age is it okay to tell ghost stories to kids? Is it healthy to, though?

AS EARLY AS POSSIBLE hahaha. Also because it gives kids 'bragging' stories. It's a reason to socialise because they have something to share. As much as we want to believe our kids sit around during recess to study, they're confirm in a pissing contest to see who has the best __________. Ghost stories definitely part of it. Also the moral part of the story up to you lah. But I'm honestly just in it to scare my kids hehehe