mach chicken
A number that means speed, but no one really knows what it is, except maybe the chicken that got slapped.
"Mach chicken is 3725.95 mph!", said by a chicken who was slapped by a chicken.
"I think mach chicken is just a made-up number.", said by a kid who got slapped by a chicken.
"Mach chicken is the speed of pain.", said by a chicken who got slapped by a chef.