There are 15 different types of distortion effects. These will give you some carnival-style effects where you can make people's heads look really large or tiny. The distortion effects can give you some fun ways to play around with your images, but for professional use, these filters don't have as much value as some of the other effects you can use. Here is a rundown of the 15 different filters you can use in the distort section of the effects browser.
The Bump effect creates a bump at a certain point in the image. With this effect, you can pinpoint where the bump should appear as well as the size and scale of the bump. You can use this on a portrait of someone to create some very funny-looking effects by putting the bump on different parts of their face to create different distortions. It's a great way to edit a photo of someone for a funny gift.