Insane and scary noise came from my wood stove?

A cold metal wood stove has metal that has contracted. When a fire is set, the metal begins to expand as it heats up. The noise you hear is the metal expanding from the heat.

You are probably right. That is what happens to me every Spring. My chimney is metal at the top, and woodpecker pecks at it regularly. It frightened the life out of me the first time. It sounded like a fire alarm going off because the sound echoes down into the room like a bell. 

Next time you hear it, go outside and look at the top of the chimney. I bet you will see a woodpecker there. 

Did you spell some popcorn kernels down inside your stove?  If you did and they started popping down inside the metal that's a truly disturbing sound

If you were burning wood which was very dry, it pops.

Mine did.

some chemical reaction