A flour bomb is a fragile container (e.g. a paper bag) filled with flour for the purpose to be thrown at a person or object to cause an inconvenient and messy stain, called flour bombing. Alternately, sometimes a bucket of flour can be used.
Flour bombs and flour bombing are a classic protest method, along with the throwing of eggs and overripe tomatoes.
The effect of flour bombs is made worse by the inclusion of eggs, or containers of other liquid, making the removal of the resultant mixture difficult.[citation needed]