Why does my cat start screaming and then have an extremely aggressive outburst right after?

Yes, cats sometimes make noises that sound like children being murdered. It can be very disturbing.

I think your cat may have some psychological problem. Lol, Ive never seen a cat do that.

Hehehe. Kitty conniption.
My cat used to blame me or the squirrells who sat outside and teased her. She made this bizarre noise that I came to associate with “Kitty kill” and she only ever made it while looking out the window at the squirrells. She’d just pounce on my foot and act like she wanted to tear it off above the ankle.
Also, somewhere, I have a picture that I took of her during a freak out session that has what appears to be a ghost in it. There was nothing that I could see when I took the shot, I just wanted to snicker about it later So who knows? Mabe your cat can see/sense a presence or some electro magnetic residual energy.
And maybe she just has kitty conniptions for no reason that a human can understand but seem perfectly reasonable to her.

bring the cat to the vet and check if he has toxoplasmosis. i had a cat that had it and he became like psychotic, attacking his own trail and legs by biting, his tail was a bloody mess, he would whirl and twirl in circles and growl at nothing. it was scary. he got medication – it’s curable. also see if your cat has anything else that may be causing his outbursts.

you know, it is possible that, like humans, he sees something outside and it makes him remember a horrible and terrifiying memory. Sometimes, that can make a person do weird things, and see things. Im no expert, but maybe it could be the same sort of thing with your cat. I mean, we both have memories and brains right?

I definitely think you should have a vet do a blood panel. If medical issues are ruled out consider that cats can have misplaced aggression when they observe something that they react to but cannot get to. The cat will take it out on anything and anybody it sees. Again, I recommend the book “Starting From Scratch”. Believe me when I tell you that you can retrain a cat.

Howling at the neighbor cat.

Type ‘redirected aggression’ into Google and ‘in cats’ is immediately suggested, lol.

just a little update, i have pinpointed the root of this problem. it is definitely, hands down the neighbor cat. i was unsure before. and he sees other animals outside all the time, squirrels, chipmunks, raccoons, and he never does anything. but this one cat, he just cant handle it. he had a LONG freakout the other day. i was terrified. i ran into the bathroom.

You should put the cat in the bathroom.

He’s horny, wants some pussy….I do the same thing.