She said: "I saw the spider last Sunday morning and wondered what was crawling up towards my open window.
"I got up and saw it, and shouted for my hubbie to come and look, as I hadn't seen a spider like this before.
"I quickly shut the window as didn't want it in my home. It was quite big, bigger than a normal spider.
"My hubbie scooped it up on my Asda magazine and put it in a bush."
Once she had recovered from the horrifying experience, Karen posted on her local Barking and Dagenham community page to ask if her fellow East Londoners knew what kind of spider she had come across.
"There were over 200 comments," she said, "Some people made me laugh with their comments.
"Apparently it is an 'Orb' spider and it's harmless, although I would never pick them up."
While we have complete trust in the intelligence of our Londoners, we wanted to be sure what kind of spider this was, and whether we need to prepare for battle if it comes knocking at our windows.
MyLondon spoke to the conservation experts at Buglife to find out.