Bend! Twist! Deform allows you to manipulate the geometry of an object or group to create looks from organic abstract animations to simpy bending text.
Each group has a set of Deform options to manipulate objects under Group/Particle Look. There are several different types of deformation options for different looks.
Tip: if you are deforming text you can go to the Model Surface Options and change the Edge Mode to from Disconnected to Connected. See Surface Options for more info.