Reverse Chihuahua Effect

A chihuahua is a little animal that makes a big noise. So in the "Reverse Chihuahua Effect", it is a big animal making a small noise.

When one tries to be meek. When physically, they are not.

When you are surprised that a meek noise comes from a large or imposing object.

When a big fat person is sneezing and makes a cute little "achoo" sound, you mention to your friend "Damn, that's some 'reverse chihuahua effect' going on".