Officials issued a health warning in the UK after Caterpillar's toxic species invaded London.
The Quercus quercus moth is present in the north of England.
And hair twill nocturnal moth larvae (caterpillar) can cause severe rashes, severe vomiting and asthma attacks.
The Royal Forestry Society also warns of dizziness, fever and eye and throat infections caused by sharp hair.
"My first symptom was a rash in my stomach. I don't know what the first thing that comes to mind is prickly heat," a gardener exposed to Caterpillar told the BBC.
"During this time I had a feeling of magic intense nausea"
Reptiles are just as dangerous as pets, who can tolerate swollen tongues, difficulty breathing and inflammation to eat or even sniff.
Moths are native to southern Europe and are controlled by predators.
But as global temperatures rise, insects are heading north, where these predators don't live.
The twill moth also severely damages their feast oak trees, stripping them of their bark before moving to the next tree.
Their hair can remain toxic on the ground for up to five years.
Caterpillars have been found in London, mostly concentrated in the southern and central cities.
But it has already been seen further afield in Essex.