it's a collection of intrusive thoughts, you've been taking care of it for so long, developing an attachment to it, putting other attachment issues on hold.
it's the most worthless precious thing you have, the rest of them might not see it, but you do. the rest of them overlook your worth, too, so casual you're not even sure it's still there.
such a funny story until it's not, an impossible theory no one can prove wrong, it's a collection of intrusive thoughts that you've been in possession of for so long.