My cat has been acting scared/angry at his own tail for the past 12+ hours.
It started when my in-laws came for a visit (3 kids included) last night.
These 5 people have all been over before and our cat has never had a problem.
After they were over for about 2 hours, the cat started growling and hissing
and pacing all around the house. When he would look behind him at his tail,
he would screech and run away. He did this for about 10 minutes before I took
him to a room in the basement where he could be alone. The in-laws left about
15 minutes later, and I went to let him out. He continued with the same
behavior for several hours, and eventually seemed to calm down a little. We
tried to give him a little catnip and some milk (2 things he loves but rarely
gets) to try to cheer him up. He ate and drank like normal, and even ate some
of his regular food. All through the night, he went through spurts where he
seemed to be normal and trying to sleep, but then would get "spooked" by his
own tail and he would start growling and hissing again. This morning he
seemed to be "normal", even letting me pet him a bit and purring. But as soon
as he sees his tail, he freaks out.

I don't want to accuse my wife's young siblings of tormenting the cat, but
nothing else in the house was out of the ordinary. Even if they were playing
a bit too rough with him, should he still be so scared/angry after 12 hours?
And why would the sight of his own tail be the catalyst that causes him to
freak out? My wife and I are planning to take him to the vet tonight if it's
not better when we get home from work, but any advice now would be much
appreciated.