Ted realizes he still has that box and wants to give the locket as a wedding gift.

Didn't your mother tell you anything when she gave you the locket?

He proposes to Peggy Sue and gives her the locket she wore at the beginning of the film.

He reminded her of the day he'd given her the locket and ring.

She gave the locket back to me.

"Maybe you want to give me the locket you took back after you killed her," I suggested.

He gives the girl the locket and whispered in her ears.

Eric gives her back the locket and asks her to dance.

The following night, he'd given Daniel the locket, the amulet as he called it, to wear.

The one who gave you the locket?