Crazed, wacked out dog whose rear legs fully extend past the front two while in a full-out running motion. When on grass, turf flies left, right and center. Can be caused by screaming a spastic "squirelly" multiple times until the dog flips out. Must emphasize that it must be screamed as: "squir-leeeeeeeeee" over and over, with enough force to make your face turn red.
Look ma, that dogs gone squirelly.