From the tutorial that I learned, the tools that were often used was the "direct selection tools", "brush tool" and "add a new layer mask". First, we use the "direct selection tool" to quickly select the subject that I wanted to crop it out and later on we need to duplicate the layer one more time so that we have 2 layers of the cropped subjects. Next, we choose the first layer of the cropped subject and we go to the "Effect" and select "Liquidify". Through the effect, we can create an effect of wrap image. Next, we add a new layer of layer mask for each of the layer and later on by using the suitable brush type to create the disintegration effect. 

https://www.youtube.com/watch?v=6roPi94D_Hw