Voice from the Belly of an Idol, -,Jinn-Spirits

Umar (ra) narrates: "One day, I was present near the idols. An
idol-worshipper slaughtered a calf, by way of making an offering for
the idols. In the meanwhile, all of a sudden, a voice came out of the
belly of a big idol, in these words:
"O strange man! a useful thing is this that an eloquent person says:
There is no god but Allah."
Umar (ra) stated that thepeople ran away gettingfrightened of this
call; but I stayed in order to know the reality of this voice. Second
time, also, the voice was heard. Thus, after some period, it was heard
about Muhammad (sallallahu alayhe wasallam) that heis a Prophet and
teaches that there is no god but Allah.
Source: Sahih Bukhari.
The voice came from a Jinn inside the belly of the idol.