So I'm turning on the light in the bathroom and I hear a rattling noise from the switch... hmmmm, what could that be. Well 20 seconds with a screwdriver reveals this...
Gecko eggs, lots of 'em. We've had an explosion of Gold Dust Day Geckos the last year or two in the house, and we've probably got these in lots of our sockets. Looks like time for a cleanout. Still don't quite know what the rattling was from.