Friends and I went island-hopping last year. My phone was changing indications of where we were several times. Names are difficult to read, much less remember. The main island where we hopped from is called Koh Chang or Elephant island.
We went to five islets each taking about 15 minutes to reach. In a stop one of my friends encountered a sea urchin. They say a pee would cure the sting. I don't know if it's true.
Another thing I heard about urchins is they could sense and would crawl towards human presence. Probably for more prickly attention?
Although sometimes paradise has a price, the sky was blue, the sun was shining, the weather perfect and the breeze was just what our city-dwelling lungs needed. All is well.