If you don’t like getting stung by bluebottle jellyfish, you’d be wise to stay the hell away from surfing Australia’s Queensland coast right now–this area is literally has been swarmed with those blue, slimy, sac-like invertebrates. According to CNN, over the first week of 2019, over 9,300 people were treated for bluebottle stings along the Gold and Sunshine Coasts–9 of which were hospitalized.

Queensland has been plagued by strong northeasterly winds lately, which seems to be the cause of this bluebottle onslaught. Apparently, these jellyfish live in a huge group in the middle of the ocean, but when the winds kick up, their sail-like crests catch the wind and blow them to shore.

“When you look at a bluebottle, and you see the bubble and the blue fringes and the long blue tentacles, that is actually a colony, that is not an individual,” Dr. Lisa-ann Gershwin, director of the Australian Marine Stinger Advisory Service told SBS News. “Some of the bluebottle sails are right-handed and some are left-handed, across the body, so when the wind comes up it only grabs the ones with the sail going the right way for that particular breeze,” she said. “It’s nature’s way of making sure the population never becomes extinct.”

Anyways, all this to say that these tentacled little suckers sailed to the Queensland coast recently and hit thousands of people. The beaches that got hit the worst and subsequently closed were Rainbow, Tugun, Coolangatta and Northcliffe. The bluebottles have left, for the most part, but some still remain on the beach. Luckily, bluebottles are generally not deadly, but they do cause a load of pain and can leave whip-like looking welts on your body for days. They could be harmful to young children, the elderly or those prone to asthma or other respiratory issues. So if you’re in and around the Queensland area right now, be safe when you paddle out.