A Dog, to whom the butcher had thrown a bone, was hurrying home with his prize as fast as he could go. As he crossed a narrow bridge, he looked down and saw his reflection in the quiet water as if in a mirror. But the greedy Dog thought he saw a real Dog carrying a bone much bigger than his own. If he had stopped to think he would have known better. But instead of thinking, he dropped his bone and sprang at the Dog in the river, only to find himself swimming for dear life to reach the shore. At last he managed to scramble out, and as he stood sadly thinking about the good bone he had lost, he realized what a foolish Dog he had been.
What is the theme?

What's the meaning of this simile?
"My mom can be as fiery as a volcano when I don't do my chores on time."

To examine two or more things in order to show how they are alike or different.