I have a foster cat, Hushpad, who's been here for about a month now.  She's
ten years old, was just spayed and had dental work done on Thursday last
week.  Hushpad weighs maybe 5 lbs and is a frail little cat.  She's very,
very clingy and requires a lot of attention.  She came from a house with 6
other cats, all in the same or worse shape as she is.

Over the time that I've been fostering her, I've kept her in my foster room,
and periodically one or two of my cats will come in the room to visit.
She's also made a few trips out of the room.  These encounters have gone
well, usually some sniffing, nose-touching, a little hissing with my
not-so-accepting of strangers cats.  Yesterday I let her out of the room for
about an hour.  It was her first trip downstairs.  I wanted to start letting
her out more, so I could observe her behavior with other cats and in a
household better for when I adopt her out.  She spent most of the time on
the couch with my husband and I, then I decided it was time to return her to
the room.

When I took her upstairs, Antonio, my little semi-feral (also a former
foster), was in the room.  I put Hushpad in and worked on herding Antonio
out (I can't pick him up).  While I was doing this, Bartleby (large
all-black, alpha-type, not too fond of stranger cats) was in the window in
the corner, and I didn't see him as not all the lights were on.  Hushpad
went up to him and I'm not sure what she did, but Bartleby turned and
swatted.  Next thing I know, the two are running around the room in circles
chasing each other, making lots of noise and scaring me to death.  I managed
to herd Hushpad into the bathroom, and Bartleby ran out of the room.  I
yelled downstairs to my husband to see if all the cats were down there.  He
said yes, so I let Hushpad back into the room.  Then, when I went to leave,
she flew out of the room like a demon-cat and went after Loki.  I again
corralled her back to the room and closed the door.  About an hour later,
while watching TV, we hear a crash.  We both go up, and the phone was
knocked off the nightstand and poor little Antonio is cowering behind a
chair. Hushpad is hissing.  I get her into the bathroom, and as soon as the
door is open to the room, Antonio flies out and down to the basement.  I
felt so awful that I mistakenly left Antonio in the room.  I triple check
for cats in the foster room, and return Hushpad.

Antonio and Bartleby were on edge all night.  Hushpad is still begging to
come out of the room, but I don't dare let her out.  It doesn't sound as
frightening in text as it was in person, but trust me, I thought one of the
cats would be seriously injured.  I guess this was a classic case of
redirected aggression.  I think I'm going to take a break from fostering
after Hushpad goes to the shelter.