Irukandji Jellyfish

It might be called MSDS or Mysterious Swimmer's Death Syndrome. For a number of years, swimmers and divers died mysteriously after swimming in waters around Queensland Australia.

They often experienced nausea, cramps and excruciating pain in their torso and extremities. Some deaths occurred within hours and were thought to be heart attacks. One reason is because a number of mysterious injuries seem similar to stings from box jellyfish, yet the swimming areas have been protected by "sting nets".

But marine biologists believe the mysterious injuries and deaths resulted from the sting of a previously unknown tiny jellyfish. The creatures are transparent and so small they can swim through "sting nets".