The amulet necklace given to Dean Winchester by his brother Sam Winchester when they were kids, on the show Supernatural.
It's called the Samulet as a combination of the name
Sam and the word amulet.
It was borrowed by Castiel in the fifth season, as he was searching for God and it was supposed to burn white hot in God's presence. It didn't
work and Castiel returned it in the episode "Dark Side Of The
Moon."
Dean, for some reason not understood by fans, threw it away, despite obvious sentimental value.