Blocks of potentially toxic palm oil the size of boulders are washing up on British beaches posing a risk to pets and children.
Known as 'fatbergs', the white waxy boulders smell of diesel and can be covered in killer germs.
See also: Family seeks justice after pet dog poisoned on Cornwall beach
See also: Cornwall beaches clean up after killer substance identified as palm oil
They are coming over from the Caribbean and have been spotted in Cornwall and Devon, Kent, Hampshire and Brighton, reports the Mirror.
When palm oil boulders washed up back in 2014, dozens of dogs needed treatment and several died.
TV vet Marc Abraham is warning animal owners to steer clear.
According to the Daily Mail, he said: "These things can cause two-fold problems, the first is gastro, the second is foreign body obstructions.
"As the palm oil is so gelatinous it can get lodged in the oesophagus and require emergency surgery.
"If you think your dog has swallowed something it shouldn't, contact your vet immediately."
Palm oil is a natural, edible vegetable which can be used in food processing but can become a problem when released legally by ships at sea.
"If you're heading to the beach please take care – while the substance has been described as non-toxic, given the reports about dogs becoming ill, we'd suggest keeping children and pets away from the deposits. And if you come into contact with the substance, wash it off with soap or shower gel and wash your clothes."