A man who dove face-first into an extremely venomous, peanut-sized jellyfish in the waters off northeast Australia was flown to a hospital intensive care unit, officials said Friday.

The 29-year-old man, whose name has not been released, was on a yacht Thursday near South Molle Island, off northeast Queensland state. As a precaution, he was wearing a full-length "stinger suit," a lightweight version of a wetsuit that covers everything but the face, feet and hands and helps protect against venomous jellyfish that are common in northern Australia's waters during the Southern Hemisphere summer.

But when he dove into the water, he was immediately stung in the face by a potentially lethal Irukandji jellyfish, Central Queensland Helicopter Rescue Service spokeswoman Leonie Hansen said. He was taken back to the island, where a rescue team rushed to his aid.

"The crew said he was shivering and in shock and in a great deal of pain," Hansen said.

The man, from the Queensland capital Brisbane, was in serious condition Friday at Mackay Base Hospital in Mackay, 600 miles north of Brisbane, a hospital spokeswoman said.

Australia is well-known for its myriad deadly creatures, but the Irukandji remains rather mysterious. It is a distant cousin of the more notorious and widely feared box jellyfish, the sting of which can kill an adult within 2 minutes. But the Irukandji is virtually impossible to see and is tiny enough to pass through nets meant to keep jellyfish away from popular swimming spots.

The jellyfish's sting can cause shooting pains in the muscles and chest, vomiting, restlessness and anxiety. Occasionally it can lead to a rapid rise in blood pressure and heart failure.