ROFL!
I moved my SVS PB-12 Ultra to a friend's place after it was sitting idle next to the entertainment stand for a good six months at my ex's place. There was a crazy buzz when the first test track hit its bass heavy section.
So, my friend and I remove the driver and there's a handful of sunflower seeds in there! When it sat idle, this sub was pushed into a corner with the lower two ports plugged. The ex never had a rodent problem in that house and I can guarantee it was never moved.
I'm still stumped as to how those seeds walked themselves from the bird feeder, into the port 20" of the floor, through the port tube and onto the back of the aluminum cone of the driver.