1. Cut your clip down to the region you want to track
2. Add the Auto Mask effect, increase both radius settings to maximum (as of making this video: 500px)
3. Press "Analyze" (If a popup appears, press merge)
4. Create a title clip, add an image, add the title clip to a track above the video
5. Select the video, then the transition and in the options of the transition, select to import keyframes.
6. Remove key frame limitation and press OK
7. Disable obfuscation in the Auto Mask effect