"I keep hearing this weird whirring noises, then scratches. All through the night. No matter if I try banging the roof or what, the sound doesn't stop."

Must be pest season, you thought.

"Rats or Cockroaches or whatever it is, I tried spraying some big spray, laid out traps and whatever anti-pest product O could get my hands on and not ONCE has the DAMN noise stop."

She looks like she's, about to blow a fuse. All red and irritated.

"Sorry. Bad habits. But you can see how big of a problem, yes?"

You nodded in agreement.

"I want to call an exterminator but, then I'll have to wait for hours for them to finish fogging the house, not to mention whatever corpse or chemical stains they'd leave, the charging price was a terrible example of 'kick when your down.'"

So she's out of option then? Perhaps it is time for you to shine your powers. You offer your help.

"Well thank you, though it is a tight crawlspace. I do hope you could find some new product to get rid-off whatever's making that racket."

You happened to have a shrinkray in your hand. By the time she went back watching her house, inspecting it, you were already shrinking down ready to find out whatever's racket Catherine is hearing.

Well, good news is you found the source of the racket. Bad news? It's no pest.

You were exploring the nook and cranies of Catherine's house, climbing to the top of it and listening in on the sounds Catherine heard in her bedroom all in secret, when you discover an empty pocket with a single box, chained and locked.

There's a key hanging by a nail on a wooden support pillar. It's as black as the lock.

The box itself was hopping and jumping around, looking as if it's trying to get out. 

You're worried you might unleashed something if you opened this box... But then Catherine couldn't get some proper sleep...

You could also shrink the box as well and carry it out of here.