The cat was there.
To make a long story short, ballistabob stumbled on the cat, and both came barrelling down the stairs, Bob trying not to hurt Scandal and the cat trying to get out of the way. This was to no avail, since ballistabob landed on the cat.
As you can imagine, we were very concerned about it. After checking that ballistabob was okay, we checked on Scandal. He seemed to be freaked out, but otherwise unhurt, so we sighed in relief.
That was 4:30 a.m.
At 7:30 we went and checked again. The poor kitty was hiding under the futon downstairs, and ballistabob found a trail of blood on the carpet and in the laundry room where his litter box is.
That's when we freaked out, threw some clothes on, and headed for the hospital, with a very quiet kitty which, in the case of Scandal, it is not a good sign.
At any rate, he has been seen by the doctors and they believe that it could be either a bruised or a ruptured bladder. At this rate, they have reason to believe that it is a bruised bladder, which has a decent prognosis. He has been sedated and put on pain medication for 24 hours. I will go visit him tonight, and we do hope that we have our kitten being his feisty little self very soon.
UPDATE- 1 p.m. = I just talked to the vet. Scandal's bladder appears to be intact, although possibly bruised. There is a big clot in his bladder, which could be reabsorbed or Scandal could pass it. The danger would be that instead of that the clot might block the urethra, in which case he'd need surgery. However, he has been urinating fine, so there is hope. He's a little anemic, possibly from the loss of blood, and his kidney values are a little bit elevated but that's a preexisting condition. I will be visiting him around 5 p.m. and hopefully will have more news.
Thanks all for the good wishes!