Australians have been warned by officials not to plant any seeds that have mysteriously arrived in the mail.
It might sound like a bizarre thing to receive, but the Department Of Agriculture, Water And Environment says dozens of packages have been sent from China, Malaysia and Taiwan to Australian addresses.
Australian authorities aren't sure what variety the seeds are or why they've been sent. One thing they do know is that it could cause billions of dollars of damage if they are invasive. But it doesn't appear Australia is alone in this strange occurrence.
These are the claims of a growing number of people in the US who have recently reported receiving mystery packages of unidentified seeds through their letterboxes from China.
The Metro reports that this bizarre trend has now made its way to the UK too - there have been around 100 reports so far - posing even more questions as to what is going on. To give you an idea of how widespread the issue is in America, warnings have been issued across all 50 states, with 630 instances in Florida alone.
Australian Seed Federation chief executive Osman Mewett said: "I'm very curious as to the motive behind it, because neither here nor in any of the overseas reports has anyone been able to explain why this is happening, where they are coming from.
"There are a few conspiracy theories out there, but I really haven't seen anything concrete as to why this would be happening. There doesn't seem to be any rhyme or reason about who is receiving these packages."
One bloke in America found out the hard way what happens when you plant mysterious seeds.
Doyle Crenshawn is one of the many people to have been sent a package of seeds from China completely out the blue.
He told 5 News: "Every two weeks I'd come by and put Miracle-Gro on it, and they just started growing like crazy. The package said it was from China and said 'studded earrings' on the outside, and we thought that was a little odd."
Authorities have now said they will come to collect the plant and carry out some tests to help identify it. The US Department of Agriculture reckons they're part of a 'brushing scam'.
This technique is used in e-commerce to boost a seller's ratings by creating fake orders. A seller might use someone's personal information to place an order themselves and send something cheap in order to validate the sale. This in turn can boost the seller's rating and bring their items to the top of search results on websites.