What grade are you in? You could dress like a turtle (which I would find interesting, but I may just love costumes too much). Or what if you did something with candy turtles. You could start with enough for the whole class, but as you went through some of the reasons turtles are endangered, you could remove them, so when you finished your presentation, the “turtles” you’d brought with you would also be endangered. Of course, it would only be fair if you then returned the ones that had been removed so everyone could have a snack.