From Daily Mail (caution: tabloid):
Giant jellyfish with tentacles up to 120 feet long are swarming US beaches, with officials warning that even dead creatures can sting.
Swarms of lion’s mane jellyfish have turned up along the New England coast, apparently by the thousands. The creatures have been spotted from Massachusetts’ North Shore to Cape Cod and Nantucket, with some drifting as far north as Maine. The beach town of Beverly in Massachusetts said last week: ‘Keep children and pets away from stranded jellyfish. … Do not touch jellyfish or detached tentacles, even if they appear dead.’ The jellyfish is known to sting even 25 days after they have died.