Comment by mindslight

If you're just talking about when something in a feedback loop gets disconnected (causing the output of the error amplifier to go to an extreme), you can do this with cruise control and a manual transmission (at least on some cars). Engage cruise control on the highway, then pop the car out of gear without using the clutch (so cruise control doesn't disengage). As the car's speed drops, the cruise control applies ever more throttle making the RPM shoot up. I've also done this going downhill with the car naturally gaining speed (and RPM going to idle).