What do you call it when the footage has a rippling effect?
They call this the rolling shutter effect.

Also known as the jello or wobble effect and is caused by the side to side motion of cameras that have the CMOS sensor.

The rolling shutter effect can be caused by:
fast moving objects, 
moving or panning the camera quickly, or
camera vibrations.

Why does this happen?
The CMOS sensor on the camera reads information a line at a time, from top to bottom. Thus different parts of the image is recorded at DIFFERENT times, thus creating the wobble effect. 

Cameras with the CCD sensor do NOT have this problem. This sensor records the whole image at once. Thus avoiding the rolling shutter effect.

There are pros and cons for using different image sensors, however it looks like we are moving to a CMOS world. 
This site below explains the differences between the sensors very nicely if you are curious.

http://www.bhphotovideo.com/c/find/newsLetter/Comparing-Image-Sensors.jsp

Hope that helps