What is in that box?!

I walked in our house door and saw a box as long as a large dog and decided to open it. But my baby brother shook his head and my mum called. “Don’t touch that box, it’s dangerous!” I ignored her and ripped off the tape and shook it a bit. What I heard was weird and surprising. I never heard anything like it.It was a low pitched squeal and a high pitched one a few seconds later, i decided to take it up to my room making sure my mum doesn’t see or hear me, I was surprised.