What is the moon, an asteroid, old planet or what

was it an asteroid, an old planet? does it have a mantle like the earth, i.e. is it warm inside or just a lump of rock?

A satellite. There are are a hundred like it all over the Solar system. Moon is one of the larger ones. Asteroids are minor planets filling the planetary slot between the orbits of Mars & Jupiter. 'Ceres' accounts for a third of the total mass of the swarm. If such same sized objects (natural satellites, the smallest planet Mercury& the dwarf planets) are arranged size wise (I did it), Mercury is 3rd, Moon is 6th & Ceres is 22nd. Being very light these are prone to gravitational effects of Earth and some times a few of them get drawn too close to it that the Astronomers call them NEOs (Near Earth Objects).
Moon doesn't have a hot core (magma) like Earth (diameter is 11/3 times) that is 49.3 times bigger. I couldn't understand your implication that of an old planet becoming a (natural) satellite. Should it be so?
There are many theories of Moon's formation & Earth-Moon system. I think we are witnessing the spectacle of Moon receding from Earth that might take a million years like any other Astronomical phenomena.

Theories are that it formed at the same time as the earth, from compounding matter in space. It was cause by gravitational force of the earth, and rotates around it. It is unlikely that it has mantle or heated core--based on the size of it and the necessity for a certain mass to allow heat capture.

one theory suggest that the moon was formed when another planet called theo collided with earth during the heavy bombardment knocking a chunk out of th planet and the moon formed from the pieces of that over the course of 1 billion years

Yavin four is a MOON, dammit. What is school teaching you kids nowadays, dating?