Christmas trees with brown, knotty clumps that look like lovely seasonal pine cones nestling among their branches could be a ticking time bomb of creepy, fast-moving insects.
The hard, brown, walnut-sized lumps, which resemble pine cones, are fact sacs containing up to 200 praying mantis eggs each.
These sacs are most commonly found at the ends of branches and your lovely warm living room is the ideal environment for the creepy crawlies to hatch out.
Molly Kreuze, from Springfield, Virginia in the US, was stunned to find her Christmas tree had smuggled hundreds of bugs into her home.
She found them crawling up her walls, ceilings and even in her bathroom and bedroom.
“They’re fast. They jump,” she said.
Luckily, Molly is a vet and is used to dealing with animals of all shapes and sizes.
She actually fed the mantises fruit flies to slow them down a little before collecting them in a box using an envelope as a scoop.
“In my Googling, I discovered that people really like praying mantises,” she said.
“They are useful, they eat other bugs. People use them for organic gardening.”
Praying mantises can grow to be up to 6 inches long, according to National Geographic . And the insects, typically brown or green, can be very hard to spot on Christmas trees and other house plants.
Daniel Reed warned unwary householders about the mantis menace on social media and his message has been doing the rounds once again this year.
He wrote: “If you happen to see a walnut-sized/shaped egg mass, on your Christmas tree, don’t fret, clip the branch and put it in your garden. These are 100-200 praying mantis eggs!
“We had two egg masses on our tree this year. Don’t bring them inside they will hatch and starve!”
One person commented: “Another reason I have a fake tree.”
A second said: “If I start seeing things crawling across the floor I will be gone until after Christmas.”
Daniel says if you see a mantis egg sac on your tree ship off the whole branch with secateurs and throw it out in the garden, where the cold will almost certainly kill the bugs.
One horrified Facebook user wrote: One wrote on social media: “A couple of years ago the egg case was really hidden because we check our trees well.
“After it was in the house for several weeks they sprang or hatched and yes a couple hundred.”
Another added: “My son had a spider nest in his.
“Christmas morning there were millions of tiny spiders all over the tree and house.”