Residents of the town of Sadiya, in Assam state, say that the spiders suddenly appeared and attacked them as they were celebrating a Hindu festival on the evening of May 8, The Times of India reported.
Over the next few days, a man, Purnakanta Buragohain, and an unnamed school boy died after being bitten by the spiders, even as many more people went to the town's hospital with spider bites.
Local resident Jintu Gogoi spent a day in the hospital complaining of excruciating pain and nausea after being bitten; his finger was still blackened and swollen six weeks later.
The most terrifying aspect is the spiders arrive in swarms and their behavior is highly aggressive.
Authorities say it could be a tarantula, a black wishbone or even a funnel-web spider, or a whole new species as it is not native to the area as there is no record of venomous spiders in Assam. The black wishbone and funnel-web are native to Australia.
There are also reports that the bite patients who died first went to witch doctors, who cut open their bites with a razor, drained out blood and burned it, which may have contributed to their already unstable state.