US Customs and Border Patrol seized a bag of giant African snails at JFK Airport recently.

The man arrived in New York on a flight from Ghana and declared his stash of 22 snails. However, the slimy creatures are prohibited due to the danger and damage they can cause.

Gothamist mentioned how the snails “eat almost anything, breed like crazy, and carry a terrifying parasite that causes something called “rat lungworm.”

Besides reproducing quickly, they can also destroy crops (they’ve been observed eating more than 500 species of plants).

The giant snails can also be pretty dangerous to people. “If the snails are ingested, or if you touch your hands to your mouth after playing with your Giant African Snail, there’s a good chance you could get rat lungworm, which is caused by a parasitic nematode that in severe cases, leads to spinal meningitis in humans”, according to Gothamist.

As for the giant in their name, these snails can be up to 8 inches long and 5 inches wide when fully grown.

The man who brought the snails into the country was not charged with any crimes since he declared his living cargo. The snails were  passed on to the US Department of Agriculture.

Find out more from Gothamist here.