Its a lens flare, but not one of the standard ones that comes with AE. I use
Optical Flares from Video CoPilot.
Here's a
tutorial on the cow on creating them just using the tools within AE. If you google "Lens Flare", "After Effects" and "tutorial" you will a lot more creative ways of creating free lens flares.
Johnny Cuevas, Editor
Thinkck.com
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.