Polly's old head

 is a piece of clothing in Fallout 76.

Characteristics
Polly's Old Head looks nearly identical to the head of an Assaultron, but has been painted on the back to say "Polly Built To Kill" (stylized POLLY BuiLT TO KILL) on top of a red heart.

Locations
Polly's Old Head is given to you by Polly in The Wayward