Little Johnny took his new chemistry set down to the basement where he
stayed all afternoon mixing various liquids together. Eventually, his
dad went down and found him surrounded by test tubes, pounding something
into the wall.

Why are you hammering a nail into the wall?" asked the dad.

"It's not a nail," said Johnny. "It's a worm! I tried to bring this
worm back to life with my special chemical mixture, but my formula made
the worm hard as a rock."

Johnny showed his dad the liquid mix that he had soaked the worm in, and
his dad said, "I'll tell you what. You give me the test tube with your
special chemical mixture in it and I'll buy you a Toyota." So little
Johnny handed the test tube over.

The next day, when Johnny got home from school, he saw a brand new
Mercedes-Benz parked in the driveway. He then asked his dad about the
car.

"Oh," said the father, "your Toyota is in the garage. The Mercedes is
from your mother."