Is it normal to want to kill cute things?
If you mean a sudden, exaggerated “I want to squish it, it’s so cute!” feeling, that’s a common reaction and usually doesn’t mean you actually want to hurt anything. If you’re worried you might act on a real urge to harm an animal or person, take some distance and get support.
That over-the-top “too cute, must squish” reaction is often called cute aggression. People can feel an urge to squeeze or nibble something adorable without wanting to injure it; the dramatic wording is usually just a way of expressing how overwhelming the cuteness feels.
The important distinction is whether it’s playful language or a real intention. If you’re concerned you might actually hurt a person or animal, put some space between you and them, and tell someone you trust so you can get help staying safe.