Are anemones dangerous to humans?

In general, sea anemones pose no real threat to humans.  However, some do provide enough of a sting to harm a human, one such anemone being the stinging anemone, which is blue-grey in color and looks a lot like a fir tree.  The stings of the anemone can cause numbness, rash, irritation, swelling, redness, pain, itching, and sometimes blisters.  The best thing to do is to use vinegar or meat tenderizer and hot water to neutralize the nematocysts (stinging cells) and then gently remove them.  A topical hydrocortisone cream can be used to treat the area afterwards.