A man who waved an air gun at a group of people in a Portsmouth car park was wrestled to the ground before he dropped the gun and escaped.
The incident happened outside the Portsbridge pub, Portsmouth Road, Cosham, on Saturday evening.
The suspect approached a group of men between 2230 BST and 2300 BST, waving the gun and shouting: "Who wants it?".
Despite being wrestled to the ground, the man broke free and ran away. Police recovered a BB gun from the scene.
The incident happened at the same time a group of women was seen arguing in a decking area next to the pub.
The women, who police say may hold vital information, also left the scene.
The man police want to speak to is white, between 5ft 10ins and 6ft tall, aged in his mid 20s, of medium build, with short dark hair. He wore a dark T-shirt and dark trousers.
Det Con Ian Cambridge said: "Although this was an imitation firearm, it looked very realistic.
"This man has caused a significant amount of distress to many customers at the pub by waving it about and causing fear."