Fx V1.0: Springy

: Makes a layer bulge (like a pillow) while it is being resized or rescaled.

: Automatically generates bounces and vibrations based on your transform properties (position, scale, and rotation). Springy FX v1.0

You can find more details and purchase the toolset on the aescripts + aeplugins store. SpringyFX Tutorial Part 1 - Installation and Intro : Makes a layer bulge (like a pillow)