Sounds like the “undercover spy gear” that was popular for a while. I think there was a cigarette case that folded open and became a gun and, of course, the ink pen telescope plus the ink pen with disappearing ink! And several others as well. It was weird… we all played outside using our imagination to create fabulous worlds in the same backyard that was a grand prix track yesterday and an undersea exploration spot the day before that. A stick was a horse one minute, a cane the next, a rifle after that , and a baseball bat… hitting home runs with the bases loaded, winning the world series. Those black walnuts would sail when you made good contact!