In
theater and
film, a squib is a small
explosive packet which is set off to give the
appearance of a
bullet or
shrapnel impact. Sometimes they may include a small amount of
stage blood when the squib is to simulate a wound.
The most spectacular squibs I've seen are in the movie Who'll Stop the Rain, starring Nick Nolte. The bloodiest (surprise surprise) are in the Sam Peckinpah movie Cross of Iron, when the recon patrol is passing through the perimeter against heavy fire from the pillboxes.