Vibrate Expression
This tag can be used to make objects vary in size, position and rotation in regular patterns (Regular Pulse enabled) or to generate random size, position and rotation changes, making the object vibrate.
For example, suppose you are animating a car ride over rough ground, see from the driver's view. By adding a Vibrate tag to the camera, you can greatly add to the realism by literally putting the viewer behind the wheel.
You can apply the Vibrate tag not only to cameras, but to any type of object.