An elderly woman suffered about 1,000 stings when she was attacked by a swarm of 75,000 killer bees that covered her entire body.
The 71-year-old, who works for telecommunications company Verizon, was hospitalised after disturbing the nest of Africanised honey bees in an underground electrical vault in Palm Desert, Southern California.
Five firefighters were also hurt as they tried to clear the swarm on Thursday.
Lance Davis, a bee removal expert, told Palm Desert Patch that the bees attacked after the woman ventured within 90 yards.
“They just went into her car and attacked her,” he told the news site. “They were mad.”
Mr Davis said her relatives tossed a blanket over her and rushed her indoors.
He said he removed the bees and planned to donate them to farmers.
Fire Battalion Chief Mark Williams said the woman, who wasn't named, suffered serious injuries but is now in a stable condition and is expected to recover.
Africanized honey bees were first discovered in the United States in 1990 and have gradually moved north.
While their stings are no worse than other bees, they are considered much more aggressive than the European Honey Bee and have been known to relentlessly attack anything they perceive to be a threat. They can sense movement within 50ft and their nests can often be found underground.
Last year, a swarm of around 30,000 bees attacked a couple in Texas as they exercised their miniature horses, stinging the animals so many times they died.