Over the last few weeks, people around the world have been receiving mystery seeds in the post from China. Nobody ordered them, nobody wanted them, but nonetheless the mystery seeds keep coming, usually arriving in packets labeled as jewelry.

The US Authorities have been particularly stern in their warnings that people should not plant the forbidden seeds – for multiple reasons – with 27 states putting out warnings, sometimes in all caps just to make you think there's something seriously dangerous going on here.

Flash forward to people all over the US planting the forbidden seeds. 

"We brought them down here and planted the seeds just to see what would happen," Doyle Crenshaw, from Booneville, Arkansas told local news network 5NewsOnline. They had arrived in a package labeled as studded earrings and he was too curious not to plant them. "Every two weeks I'd come by and put miracle grow on it and they just started growing like crazy."

Some of the plants have orange blossoms and long white fruits, which could mean it's a squash. So far, there are no signs of the plants attempting to eat people as Internet memes would suggest is next.

Crenshaw is far from alone in his curiosity.

The seeds are a mixed bag, but so far have been fairly innocuous. An investigation by the US Department of Agriculture (USDA) found that they were pretty ordinary varieties you'd be able to buy at a store.

"We have identified 14 different species of seeds, including mustard, cabbage, morning glory, and some herbs like mint, sage, rosemary, lavender, then other seeds like hibiscus and roses," Osama El-Lissy from the Plant Protection program of USDA's Animal and Plant Health Inspection Service said in a radio interview. "This is just a subset of the samples we've collected so far."

You probably still shouldn't plant them though, as they could contain pathogens or contaminates, insects could be hidden within the packaging, or the seeds themselves could belong to invasive species. The USDA urged anyone who receives an unsolicited bag of seeds to contact their state regulator and hold onto the package until they are given further instructions.

As for an explanation why China appears to be gifting the world mysterious seeds, so far an online scam is the most likely scenario.

"At this time, we don’t have any evidence indicating this is something other than a 'brushing scam' where people receive unsolicited items from a seller who then posts false customer reviews to boost sales," the USDA said in a statement. 

Essentially, people send out the packages to random people and then review the product under a false name on sites like Amazon or Etsy. This then boosts their seller rating, and their actual products (probably not seeds) start showing up in more people's search results while they shop.