A man threatened to kill two teenagers with a knife in Weston-super-Mare on Thursday.
The two youths were walking along Wansborough Road at around 1800 BST when a man walking in front of them stopped and drew a knife.
He threatened to kill the boys who both ran off.
The man is described as white, aged in his late 40s or early 50s, of medium build and about 5 ft 6 ins tall.
He had a tanned complexion and was wearing black trainers, blue jeans and a t-shirt.
Police are appealing for witnesses.