"Slay" is a funny word. I think of it mostly having a connotation of a just person killing something evil. So I could slay a dragon, but not a chicken.
It almost becomes fully inverted in the Legend of Zelda games. I think this behavior is there in the whole series, but in Ocarina of Time in particular, if you kill a chicken, there's a dramatic cutscene of the chicken dying which foreshadows the chicken's brethren registering your evil. They then chase and attack you. You can't fight the horde back, so they eventually kill you unless you get indoors before that occurs.
It has connotations of heroism.