Experts are trying to identify the species of spiders that have invaded an Indian village, reportedly killing two people and injuring many others.
Panicked villagers in Sadiya, Assam, said swarms of the creatures began jumping at people and biting victims during a Hindu festival.
Indian media said a dozen people had been bitten and treated in hospital and two had died.
"Initially we thought it was a prank, but later on we saw swarms of this peculiar kind of spider biting people," Ranjit Das, a community elder said.
Authorities have swung into action by fogging and spraying insecticides in the area, 370 miles east of Assam's main city of Guwahati.
A team of scientists have been dispatched to investigate.
"We visited the spot and found it akin to the tarantula, but we are still not sure what this particular species is," said LR Saikia, a scientist from the department of life science of Dibrugarh University in Assam.
"It appears to be an aggressive spider with its fangs more powerful than the normal variety of house spiders," Mr Saikia said.
"It leaps at anything that comes close. Some of the victims claimed the spider latched on to them after biting," he added.
Specimens have been sent outside Assam for identification by arachnologists, he said.
The Times of India reported that a schoolboy has died, along with another unidentified victim.
It is unclear if the two victims died from the spiders' venom, as both were cremated before post-mortem examinations could be carried out.
Dr Anil Phatowali, superintendent of the town's hospital, said he could not be sure if the spiders were even venomous because he did not administer an antivenin dose.
The bite victims may have fallen ill because they went to witch doctors before seeking hospital treatment, Dr Phatowali said.
The witch doctors opened the victims' wounds with razors and drained their blood.
"That could have also made them sick," the doctor added.