object lesson

object lesson (plural object lessons)

1. A lesson taught (especially to young children) using a familiar or unusual object as a focus.
2. An example from real life that typifies/explains a principle or teaches a lesson.
3. Anything used as 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.

   Let that be an object lesson to him.

• life lesson