How do I get my cat to stop freaking out?

[Nemean Lion]

In 2002 we got two cats from the pound. One is a sleek black male with siamese influence named Ebony, more commonly Eb. The other is a gray cat named Gray Cat (I was seven), called Grace. She is definately a descendent from Persians and perhaps other long haired breeds, and, as I have now learned, appears twice as large as she actually is because of the volume of her fur.

We've always had a problem with Grace's shedding (We got rid of a chair because it was covered in her fur), but recently it has been causing her to hack up hairballs on a cycle of two or three days. Desperate, my mom called a groomer and had her shaved. She now looks about half her old size, but her puffy fur remains on her head, the half bottom of her legs, and the tip of her tail (it's actually quite funny). Our other cat, who has occasionally been territorial and aggressive, doesn't recognize her and is hissing, fluffing up, attacking her, and making sounds I would expect more from a possessed child than a cat.

How can I get him to realize it's still the same cat?
(Also, was the poodle-style tip of fur left on the tail purely for asthetic reasons or does it have a purpose?)

[Catlady711]

How long ago was the cat shaved?

With my cats it can take a day or two for them to settle down after a vet visit (longer if anyone pees on themselves while there). When that happens I just shut the one having the fit in a room by themselves for a day or two until the other cat(s) smell like home again and gradually allow them out supervised for awhile until things are back to normal.

Good luck.

[Medusa]

What Catlady711 said.