My belly makes dreadful rumblings, loud gurgles, and scary sounds.

Usually just before, erm, clearing out a room. To put it politely.

Moreso than just that though. I've been told (by one cute little girl) that I have monsters in my belly. I've had my stomach make gurgly growls so loud and so fierce that it has made my dog jump up, hair sticking all out, and growling at my tummy.

Etymology - He of frightful guts.