Someone recounted to me a science-fiction short story (sort of in the style of Robert Sheckley, but I am not saying he was the author -- I don't know) whose plot goes like this: on a planet, at first thought to be uninhabited, some scouts hear something coming from a forest; they shout questions, and answers which sound like mocking come back. The scouts report, and the delegation goes there, and warns whoever is in there to come out or be shot at. They shoot some warning shots into the forest, and are immediately met by return fire. The delegations then shoot even more into the forest, and again are met with even heavier fire, some of it deadly. This goes on until the delegation is wiped out. In the end, there was no one in the forest; it was a sort of "echo" that came back, although not only sound but objects. A sort of interactive mirror. That is it, more or less. If anyone knows this story, please tell me whatever leads you can give so that I can identify it. Thanks.