I will explain what happened in two different ways.
We had just brought home my little Erandir, and he was getting used to the house ... I took him downstairs to the basement to get him used to it down there, and the other cat had followed down and was being extremely aggressive. He'd cornered him and was hissing and yowling in his face and acting like he was about ready to claw his eyes out. Erandir was submissive...
So for a while, Gizmo was down there glaring and growling and hissing at Erandir making the cornered cat terribly frightened. Then.. this girl, a friend of my bf's roommate, came down to look at the kitty, bringing the hyper Baily with he. The dog was all hyped up and jumping all around, and the girl was egging her on and calling her over to the cat when I warned her that the cat was terrified of the dog. The cat was still cornered behind the tv, by the dog, the aggressive other cat, and now this person reaching out, rather quickly, to pet him. He hissed, he growled, he frizzed out and gave plenty of sign. He wanted to be left alone. I warned the chick. I told her he was terrified and might bite or scratch. ANY animal would. His claws were clipped short... The dog was still being hyper and shoving her head between the chick's legs to sniff at the cat and the chick reached out to pet him and he bit her.
Any cat would have.
He was SCARED. He was stressed. He was in a new place. He was fucking defending himself! How was he to know that sudden moving thing wasn't something dangerous?

Now think of this from his point of view.
You were in this small cramped cage for gods know how long... people tapping on your cage... other stressed cats around you.. noise, barking in the background...
Then, you finally get out of there to find yourself crammed into a tiny little cage. The cage is moving. There are noises outside, but you can't see what's going on. Then your cage is picked up, put on a couch. After a moment, it is opened.
Everything's.. different. you don't know where the hell you are, and suddenly, this big brown monster THING comes at you. It makes these deep huffing breathing noises.. it has a mouthful of teeth larger then your HEAD. The beast moves away.. you finally have the nerve to leave the cage. You are gently picked up... you you remember that scent. Those were the nice people who got you out of that place. Maybe this is... finally your new home. Maybe you're out of that terrible place... You are taken into a room down a flight of stairs and set down. Ah, there's the bathroom, though it's a bit dirty at the moment.
Suddenly, another creature, like yourself, comes rushing at you snarling and hissing and looking like it wants to kill you. You do all you can.. submit.
The beast finally leaves. You are alone.
But not for long. You've been there for a while, starting to feel comfortable.
When it comes down again. Screaming in your face, acting like it wants a piece of your ear. Then.. he's just glaring at you. You're cornered, nowhere to go! To scared to run up the stairs... never been on those stairs yourself before without a human. That thing might attack!
You hear footsteps on the stairs.. oh gods not that horrible brown beast again... it comes rushing right up to you with that mouthful of terrible teeth. Where could such a horrible beast have come from? what the HELL is it doing in your face? It might attack!
Suddenly, something else comes rushing at your face.
Your only defense is your teeth and claws, but your claws are useless. They are clipped almost to the quick.
Hoshit You have to do something fast! You're mind is clouded with terror, stress, and now that thing is rushing at you... you are enveloped by the scent of that evil brown beast with the big teeth...

It's not fair. We can't keep him! Erandir can't go back to the pound! He bit somebody.. they would put him down in an instant. He would die. But we have to find a home for him by tomorrow night... and I can't take him to Arpie's... she has rodents, and cats eat rodents. So that is probably out of the question.

I don't know what to do.... I can't stop crying. I love this cat... he loves me. He's a sweetheart.. and so beautiful.. and so perfect... I've wanted a cat all my life and now my boyfriend's roommates are going to make him get rid of him and I can't take him to where I live now because I live in a friend's living room, and she has rodents... They're caged but still.. cats eat rodents, rodents are terrified of cats...

And there's nowhere for him to go. He'll probably be put down...