Just when you thought it was safe to go back into that snakehead fishpond behind the shopping center in Crofton, Md., now comes word of a new threat slithering into our environment.

It’s big (five to seven feet long), it’s bad (it can carry cholera), it’s hot pink (nearly fluorescent), and it’s coming soon to a bait shop near you. It’s the Nuclear Worm (genus Namalycastis), Vietnam’s biological revenge for all that napalm and Agent Orange 30 years ago. More here.

The US Fish and Wildlife Service is on the case. Shipped in via San Francisco, where it’s probably just another lifestyle, the nuclear worm has been welcomed into Chesapeake Bay bait buckets like a bloodworm wired on Viagra.

Born among the tropical roots of Vietnamese coconut palms, it needs no refrigeration and can live for days on the dashboard of your overheated car. Rockfish suck it up like sushi. Is this something you’re likely to step on barefoot one night when you’re taking out garbage?

‘‘There are a lot of unanswered questions about these worms that cause us concern,’’ says Mike Slattery of the Fish and Wildlife Service’s Chesapeake Bay field office in Annapolis.

According to a 2001 report from Slattery’s office, live-worm imports alone were a $70 million business in the US from 1998 to 2000. Nuclear worms are a relative drop in the bucket, he says, and nobody really knows much about them.