The kind that sting! I got stung up north near Basil Jones when we were stopped for a lunch stop. I was gathering some driftwood and one dropped out of the wood and landed on my foot. Felt like a cross between an cattle prod and someone holding a lit cigar on my foot. Vincent, out guide, said it was not a bad one...(that's easy for him to say-it wasn't his foot) because I could still walk on it. The pain lasted all night and it was still tender the next day. I was definitely more cautious the rest of our stay. On the bright side-we had a great time and are already planning for next year's stay on AC!