A cargo ship arrived a port in Belgium with some unexpected passengers, after crews discovered an infestation of wolf spiders.

According to Bloomberg, the Glovis Sun — carrying a couple thousand cars as its cargo — had recently traveled around Southern Africa, before arriving at the Port of Zeebrugge on July 18. After coming on board, port officials found a "significant amount of spider webs" spun across cars and parts of the ship. The vessel was then locked down for two days so that exterminators could be brought in to clear the infestation and send the Glovis Sun on its way. 

Wolf spiders can grow to more than an inch in length and, like their namesake, will chase and pounce on their insect prey, before (unlike their namesake) mashing it up into a ball and injecting venom into it to liquefy its organs. Its bite is generally considered to be harmless to humans and pets, although it can be painful. The spiders are native to a variety of regions and climates across the globe, ranging from suburban gardens to coastal dunes. 

Pests also aren't uncommon on cargo ships, according to logistics service Shipmate Fulfillment. Termites and beetles are known to crawl into wood shipping crates, while ants can be carried aboard vessels by moths and other flying insects.

Sometimes, the results are disastrous. In the 1990s, solid wood packing material from China, including wooden pallets used for cargo, became infested with Asian Longhorned Beetles. According to the United States Department of Agriculture, these wood-boring predators spread to New York (1996), Illinois (1998), New Jersey (2002), Massachusetts (2008), and Ohio (2011), and resulted in the felling of more than 150,000 trees.