Unusual Abyssinian Behaviour

Question
Hi Norman,

My 78 year old Mother has a 2 year old beautiful, neutered, indoor female
abyssianian cat who has recently started showing some unusual behaviour.
Cleo, the cat, recently saw a black cat in front of the sliding door and began
yowling, hissing and running around the livingroom in a very upset manner.
Since this incident, Cleo has demonstrated this behaviour at night while
looking out the sliding door when there is no cat in sight or jumping off my
Mother's bed late at night and doing her cat scream and running around the
house etc. The only way my Mother can get her to stop is to lure her with a
treat into her windowless laundry room for the night. By morning Cleo is okay
again.  When Cleo gets this agitated there is no calming her down. My Mother
is actually afraid of her behaviour and doesn't understand it, or how to handle
it. I guess another reason my Mother is uncomfortable is her cat looks at her
while she yowls and that creeps her out. Any thoughts?  Thank you

Prior to these recent episodes, Cleo has been a very friendly, active, playful
and affectionate cat.  

Answer
Yvonne,

This is very normal behavior in a cat defending its territory from a perceived interloper (the strange cat).  What you have is the standard fight/flight reaction to a fearful situation for Cleo.

Putting her up to chill till morning is a proper thing to do.  The odds are the cat will not hurt any humans in this state of agitation.

Once the strange cat no longer comes around, within a few weeks, Cleo should forget all about it and return to being friendly, active, playful, and affectionate.

Best regards... Norm.