The small guy said, "I am brown. I am from Pluto and I am hungry."
Robbie shrugged his shoulders and said, "Well, I can offer you my sandwich, little fella and that's about all I can do."
Robbie gave his sandwich to the little guy and drove off. After a little distance, he noticed a small red guy standing in the middle of the road waving his hand. Robbie stopped the truck and asked the small guy what he wanted.
The small guy said, "I am red. I am from Mars and I am thirsty."
Robbie getting a little impatient, said "All I have is a bottle of beer. You can take it, but that's about all I can do for you."
He handed over the beer to the small guy and drove off. He had covered only a few miles when he saw a small blue man in the middle of the road.
Robbie, a little irritated by then, stopped his truck and said to the guy angrily, "Yes, you idiotic blue joker. Which godforsaken planet are you from, and what do you want?"
The little guy replied, "May I see your Driver's license, sir!"