Styrofoam packing nuts. They will likely fall out of use, then people will forget about them. Finally, as they reappear centuries later, people will start colle

Styrofoam packing nuts. They will likely fall out of use, then people will forget about them. Finally, as they reappear centuries later, people will start collecting them until they find a completely intact Amazon package of seeds from an extinct plant… and packing nuts. Then, the mystery will be solved; The ancients must have believed that these packing nuts could preserve objects since the styrofoam itself would last forever.