When I went to the beach recently, this poor little starfish was stranded after the tide had gone out and I felt bad, so I put him into a little pool of water that had been left.
I read later that they can survive for up to 5 days without water, so he probably didn't really need my help at all, and he might actually have been enjoying a bit of fresh air, so perhaps next time I'll just say hello and walk on by.