Can you identify this anime?

This anime might have been a short movie that was an extra on another dvd set.

It was about a guy who starts seeing these bug-like things attached to peoples backs. I think he has the urge to eat one which makes him realize that the 'bugs' are the regrets or bad memories of those people. When he eats them the people become happier. After trying to help people by eating their invisible 'bugs' he notices they might have been better off keeping those memories.

I know that's not much to go on, but any help would be great!