When I was a wee lad, my bedroom had one of those closets with the two sliding mirror panels.
One day, I look in between the panels, and I spot not one, but three black things with little red marks on them. I thought nothing of it, and went about my business.
Eventually my curiosity got the better of me and I asked my parents what they were. Next thing I knew I was sleeping in the guest room for a few nights.
A few years later, I found out they were black widows. I had three of them a few feet from my own bed.