When I was little I learned to tell the difference between certain kinds of snakes that were poisonous and those that were simply mimicking the coloration of their deadly cousins through the rhyme: “If red touches yellow, you’re a dead fellow. If red touches black, you’re okay, Jack.”
Writing Prompt: Red and Yellow, You’re a Dead Fellow (M)
Invent a deadly species–an alien species; an earthly monster; or a speculative version of an existing species like a spider, bird, snake, berries, mushrooms, etc.–and come up with a catchy rhyme the people in your story use to tell the difference between harmless and harmful cousin species with similar appearances. Write a story in which your character is thrown into a situation where they have a close encounter with one of these species and they can’t remember the rhyme that tells them whether this creature is safe or deadly–they have to figure it out another way. Bonus points if you administer the wrong antidote, or if getting past these creatures is vital to some other urgent goal on the journey.