A vicious hoard of flying insects has been terrorising beachgoers by biting or darting into their mouths, ears and noses.
Thousands of the tiny 'thunderbugs' have sent holidaymakers in Essex fleeing as the pests attacked visitors in huge swarms.
One beachgoer described her ordeal on Monday as a "nightmare" and said her three children were bombarded by the insects - believed to be storm flies.
Hannah Faulkner-Hatt, 40, said: "We were trying to get back to the car as fast as possible.
“They were flying up our noses and in our ears. It was horrible. My partner was choking on one in the car.
“It was a nightmare. The kids weren’t best pleased when we were being attacked by them."
Thunderbugs, or thrips, can be as small as 1mm and have been known to bite humans - but they only cause minor irritation.
Hannah said that the critters forced holidaymakers on the promenade in Southend, Essex, to cover their faces to escape the pests.
She added that the monkeys at the SeaLife Adventure zoo were even spotted eating the bugs as they flew into their enclosure.
Hannah said: "The air was full of them. You couldn’t see past them.
“Everyone was talking about it along the seafront. They were everywhere.
“The monkeys were having a lovely time. They had plenty of bugs to choose from.”
The black storm flies were also seen swarming cars and car windows.
Carole Mulroney, Lib Dem Southend councillor in charge of the environment, culture, tourism and planning, said: “We get this once a year, but it’s usually flying ants.
“The little black ones are almost definitely storm flies.
“It usually means there’s a sign of a storm coming, but we did have rain the day before.”
The flies have also been known to invade homes and gardens before a storm.