1. Start by opening Photoshop and creating a new RGB image. Create a new layer. Stretch a line from the top of the image to wherever you like (long enough for the shear though)...and set the width of about 50 px. 2. Next, click on Edit > Transform > Perspective. Modify the settings to have a result similar to the tentacle in the example on the left. 3. Now click on Filter > Distort > Shear. Alter your image to fit what you need. Remember dont over do it...that usually spoils it. 4. You're done, but I suggest adding some layer effect (double click on the layer) just to make it look a bit better. And you're done.