a lesson taught (especially to young children) using a familiar or unusual object as a focus
Anything used an example or lesson which serves to warn others as to the outcomes that result from a particular action or behavior, as exemplified by the fates of those who followed that course
If you describe an action, event, or situation as an object lesson, you think that it demonstrates the correct way to do something, or that it demonstrates the truth of a particular principle. It was an object lesson in how to use television as a means of persuasion. = example