[Bhikku]

Here's my advice:

1. Get your dog checked at the vet immediately. Sudden aggression can sometimes be explained by a hidden illness or injury which is very painful for the dog, causing it to lash out.

If you have the dog checked and no physical problems turn up, I'd try the following:

2. Does she have a crate? Any time she growled or snapped at anyone, I would scold her very firmly (No! Bad girl!) and put her in the crate. That way she'd know that aggressive-possessive behavior is not acceptable.

3. I'd probably chase her out of her bed anytime she started throwing a tantrum and sit on it myself. That would show her that you were the alpha and that the dog bed is yours, not hers. You're just letting her use it.

4. I'd try spraying her in the face with a water bottle, blowing an air horn, or squirting her with an aerosol keyboard cleaner (canned air) any time she shows aggression. The noise or sensations will startle her out of an aggressive reaction and give you a chance to scold her.

5. Like Elle said, I wouldn't pop her. It'll just confuse her further and usually that kind of response just heightens defensive aggression.

6. Immersion therapy: Try blocking her access to the underside of your bed. If she is showing nervous aggression, this will force her to confront that overexaggerated fear rather than seething with anxiety in a hiding place.

Hope that helps. Keep us posted.