The bodies consist of a bell and many trailing tentacles. Jellyfish are poor swimmers and usually are found drifting in the water. In a strong current, jellyfish can be washed onto the shore, causing problems for barefooted people who aren't watching where they are walking. Jellyfish have stinging cells usually found on the tentacles, but sometimes in the bell. Injury can result from skin contact with any part of the jellyfish.
Exposure causes pain, redness, itching, swelling, skin irritation and blisters.
If exposed to a jellyfish, do not rinse the area with fresh water and do not rub the area. These measures will cause stinging cells to fire further, causing more pain. Call the Poison Center for more advice. Stingrays have a barbed spine on their long tails that can cause painful and dangerous stings. Stingrays can thrash their tails side to side and up and down, causing glancing blows as well as actual stings.