When you saw a one eye car (that means a headlight would have to be out) you slugged the person next to you and said "Perdinkle" [or "Pudiddle" in later years]. Then you would have to show them the car your were calling on.
If the car was in fact a motorcycle instead, the person you hit gets to hit you back 10 times.
For "Slug Bug", the rules were the same except you hit the other person if you saw a Volkswagen Beetle.
Contributed by Deborah - Thank you!