An unattractive girl that is also overweight. However, rollerpigs are just thin enough to be picked up by intoxicated men when desperation sets in just before last call.
Did you see that rollerpig Brad hooked up with last night? He'll never live that one down!
A person in a wheel chair, typically because they are too fat to use crutches.
A rollerpeg is a person who breaks their legdancing and because of their weight, they opt for a wheelchair instead of the recommended crutches. In some cases, the person may acquire a handicap parking tag in their car.