A postal package shipped through San Francisco International Airport contained, under further inspection, some surprising contents. During a routine scan of packages traveling through the airport, 20 foot-long millipedes sent without permits from Europe were sent to the U.S. on Friday.

Authorities in the U.S. Customs and Border Protection agency found the live millipedes in a foam container along with soil and paper stuffed into a mesh bag. The outside of the package was marked "toy car model."

CBP said the package had been shipped from Germany and was accepted at the U.S. Postal Service International Service Center in the San Francisco airport.

When the package was sent through an X-ray machine for inspection, agriculture specialists noted something strange about the large plastic foam container.

"[Specialists were] quick to notice the deception and took the necessary action," the agency's director of Field Operations in San Francisco, Brian J. Humphrey said in a statement. Whoever sent the package was believed to be trying to get around federal regulations by "misrepresenting" the contents and not having the required import permit.

While importing these exotic animals is not illegal, agencies regulate these types of imports to check proper documentation has been granted. CBP spokesperson Fred Ho said that these millipedes were likely intended as exotic pets.

Customs seized the insects before they could get to Vista, California, and their intended buyer. The sender in Berlin was issued a postal violation. The millipedes were then euthanized and are being held with the U.S. Department of Agriculture, according to customs officials.

Millipedes are slow-moving arthropods that have multiple body segments with dozens of pairs of legs along their bodies. The insects don't bite and can live for several years on rotten produce, but some do secrete poisonous liquids.