You've got a bad egg there. No, literally. How often have you wondered whether or not the eggs you have on hand are fresh? You can't exactly smell them (unless they're rotten, that is), but luckily there are a few dead giveaways that you need to toss them ASAP.
First you need to.....
1. Fill a fairly deep bowl almost to the top with cool water.
2. Gently place an egg into the bowl, being careful not to break it. If the egg floats, it's a bad egg. If it sinks, proceed to step #3.
3. If the egg lays flat along the bottom of the bowl it is fresh. If it stands on one end, it's still fresh, but less so than if it laid flat. Both of these would be safe to eat, but you should eat the egg that stands on one end first.
4. If you're even the least bit hesitant about a carton of eggs, test each one just to be on the safe side.
Last one to do so is a rotten egg! Sorry, had to do it :)