SINGAPORE (CNA) - Box jellyfish, which have a painful and potentially fatal sting, have reportedly been sighted in Singapore's waters, prompting the Sentosa Development Corporation and a local marine conservation group to issue advisories on swimming in these beaches. Sunburn, for example, could harm the delicate creatures. World's Most Poisonous Animals 1. They . 1. YouTube/Steve-O But, if you should ever get stung, here's some advice from . Amusingly enough, it is also not a real jellyfish, but rather something called a bluebottle. Numbness or tingling. The eastern brown snake - deadly. Peruvian Jellyfish Stunt - Steve-O - YouTube This jellyfish is made up of colonies of marine organisms that live in its sail-shaped gelatinous pouch, which measures 15 to 30 centimeters. The 10 Most Common Peruvian Sea Animals - Life Persona Poisonous jellyfish on the rise in the Mediterranean The sting of a box jellyfish can kill a person in minutes. Blue Red Jellyfish on Black - The ocean jellyfish searches for fish prey and uses its poisonous tentacles to subdue the animals it hunts. 4. The cannonball jellyfish (Stomolophus meleagris), also known as the cabbagehead jellyfish, is a species of jellyfish in the family Stomolophidae.Its common name derives from its similarity to a cannonball in shape and size. The Portuguese man o' war, ( Physalia physalis) is often called a jellyfish, but is actually a species of siphonophore, a group of animals that are closely related to jellyfish. Baby fish lose poisonous protectors in acidified oceans Vidar Nordli-Mathisen on Unsplash. Jellyfish: Beautiful, dangerous, delicious - CBS News