A bullet hit squib or a blood squib is a practical, pyrotechnic special effect device mainly used to simulate the appearance of a person being shot and wounded in the film industry, stage performances and even in first responder moulage training. This is achieved by remotely detonating a small explosive hidden in the actor's clothing, bursting a fake blood packet and blowing open a pre-scored hole to create an aesthetic that filmmakers and audiences alike have become accustomed to associating with a gunshot wound.
The device comprises a squib (a small, tablet-shaped, firecracker-like explosive) with an integrated igniter or glow wire, a pack of simulant (often fake blood), a protective shield and padding attached to the actor's costume. It is connected to a battery and a remote, allowing the squib to be triggered by the actor or a crew member.
The effect is usually carried out with clothing instead of on bare skin in order to conceal the device. While the portrayal is not necessarily accurate or is exaggerated compared to real-life (in the main figure, bullet holes are blown outwards and blood projects through the fabric), it is nevertheless a useful tool to create a dramatic scene.