Pilot Induced Oscillation. New pilots are often too abrupt on the controls causing an overshoot of the desired altitude or airspeed followed by hasty over correctiontrying to maintain a desired state. This results in a porpoise like undulation.
The craziest motherfucker on the road, He will do anything to beat you in a street race. Likely to get in a crash and chronically plays 2-step as the only song while he's driving because it has excessive bass to it.