A moment of threat before the relief occurs, via the cat's doing, still. A character investigating noises in their house sees the killer lunge at them, but it's really an old cardboard cutout pushed forward by the family cat rushing to greet the character.
The cats owner jumps out and frightens it on purpose...then the real threat arrives as the owner is oblivoius to his pet's continued reactions
A character, hearing something scary, goes to investigate. The cat jumps out. We expect something worse to happen, it doesn't. It's really just the cat.
Or else, the cat jumps out, and the character is initially relieved after the scare, but it turns out the cat is the monster and it kills the character.
Double Subverted: A character investigating frightening noises has the cat jump out at them, and feels relieved, nothing happens for a good while. And then the psycho jumps out.
An intelligent cat hangs by its claws from ceilings and makes a bunch of noise so it can jump out at those who investigate and laugh at their reactions.
A character investigating frightening noises finds a cat... it's a Panther. note And if they really want to parody it, it's not a Panther, it's a Panzer.
A cat walks through the house, we hear strange noises... then someone jumps out at the cat.
Zig Zagged: The cat is the psychopath, and tries to kill the character. But wait, no it's not, it was just very startled- it's harmless after all. Wait a minute, the cat couldn't have made all that noise, there must be something worse there! Wait, no there isn't... Then we see the psycho jump out... or rather, his body falls out of a nearby closet, as he's already been killed by... the cat, who proceeds to give a sinister meow and then...
Averted: A character investigates strange noises. The killer pops out right away.
Enforced: The hero is way too smart and fast to be surprised by the clumsy, slow monster. So a Cat Scare is used to lower his defense and let the final showdown begin.
Lampshaded: "Oh, it's just the ca- wait a minute, there's something worse waiting for me, isn't there?"
Invoked: A killer hides in houses and throws cats at those who investigate in order to keep suspicion off himself.
Defied: When the cat jumps out, the character is not at all relieved and gets ready to face whatever else is lurking.
Discussed: "Uh-oh. The cat jumped out at me. I shouldn't be relieved, it probably means something worse is going to follow."
Conversed: "No no no! Augh, she thinks the noise was just the cat- how could she be so stupid?"
The cat actually scares the victim into a fatal heart attack, and the killer finds their dead body.
The killer is actually a pissed-off feral cat.
Reconstructed: Cats are benevolent creatures that are trying to warn the hero.