: an act of showing someone how something is used or done : demonstration. 1  I saw a demo on how to use the computer program. 2  The salesman gave us a demo of the vacuum cleaner, and it seemed to work very well. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples 3
If however, you are talking about some maggots in a bowl of wet food (either canned food or dry food which got wet or which you deliberately added fluid to) it is a different matter. Maggots come from flies eggs and they take some set period of time to hatch from the eggs.
Maggots are the larvae of the adult blow fly. If produce, meat or even fecal matter is left out in the open, the adult flies seize the opportunity to lay their eggs in this warm, moist and nutritious material. Within several days, the eggs hatch into maggots, and several days later, the maggots mature into adult flies.