It’s a common thing in time travel stories for an object to only exist because of the time travel - someone from the future travels back in time, and gives an item to a character, which they then carry to the future and either travel back in time to give it to themselves, or pass it off to someone else to pass on to them in the past.
I’m 90% positive I, at one point, knew a term that referred to that object, but I can’t, for the life of me, remember what it is.
Note, I’m not looking for ‘closed time loop’, ‘predestination paradox’ or anything like that. It’s not the situation, it’s the object.
They’d be a form of OOPArt, one supposes, but again, I’m trying to remember a vaguely remembered term for a time-displaced item that only exists in the first place because it was time-displaced.