1. Ouch!! An up-close look at the mechanics of a jellyfish sting.

2. How we did it… One of the stinging tentacles was placed under a microscope and observed at different magnifications…

3. Step 1: Contact Contact with a jellyfish tentacle stimulates hundreds, or even thousands of specialized cells called nematocysts.

4. Step 2: The Nematocysts • There can be millions of these specialized stinging cells on a single tentacle. These arrows are pointing out only a small fraction of them! • This is less than a millimeter of the tentacle at 100X magnification. • Each little circle contains a painful nematocyst. • These cells are the culprits of the pain! • Can you count them all?

5. Here are a few more images illustrating the extreme density of the nematocysts.

6. Step 3: The Release • Once contacted, each individual nematocyst releases a harpoon-like structure. • As the harpoon pierces your skin, it unfolds and releases painful toxins into your body. • The severity of the sting depends upon the type of jellyfish, and the amount of nematocysts that enter your body. An untouched nematocyst! Can you see the harpoon coiled up within the cell?

7. Here are more nematocysts that have fired, under 100X magnification… And now under 400X magnification.

8. PUNCH! So remember! Even though the jellyfish, or even just the tentacle may be small, it can pack quite a…