My Piper had the exact same thing a few months ago. However, he had LOTS of blood in his stool.

I rushed him to the emergency vets, who gave it a name (I can't for the life of me remember what it was called, but it was an acronym of some sort). They sent us home after giving him something for his tummy and subcutaneous fluids to rehydrate him, with orders to take him to his regular vet the next morning. Of course, I was petrified and couldn't sleep for watching him all night.

As it turns out, our regular vet told us that the acronym basically stood for the symptoms, which is a really severe irritation of the stomach lining, blood in the stool, diarrhea and vomiting. It could have been caused by swallowing a foreign object. He told us he would be okay, and that it would have to run it's course. We didn't give him food that day, and started him on a bland diet for the next couple of days (boiled chicken, white rice).

He's fine now. We still don't know what caused it but my suspicion always was that it was some of a stuffie that he had played with the previous day that he tore to shreds while I was in another room of the house. He only had it a matter of minutes, but that's all I can think of that it could have been. I kept watching for him to "pass it", but never found anything.

I hope this helps. I'm sending up a prayer for Beaner.