Weird Trackpad glitch

[oldschool]

every so often, my trackpad starts acting up. It moves all over the place as if i have another finger on the trackpad at the same time. I know that its not water or anything on it, because if i press Command+option+D it goes away.....don't ask me how i figured this out.


Any reasons why?

 

[Kyle]

My new iBook G4 does this, too.