Everything you need to understand or teach The Cat's-Eye by Jim Murphy.
Murphy's short stories tend to have forthright plots and easily identifiable good and bad characters, but "The Cat's-Eye," from the collection Night Terrors, is an exception.
Heroes and villains are hard to distinguish, and its moralistic theme raises ethical issues that are difficult to resolve. The result is a layered story with a traditional plot structure that overlays a foundation of complex characters and challenging ideas. The blend of plot, characters, and theme works well, making "The Cat's-Eye" a particularly satisfying read. That the ethical issues it raises remain troubling after the story is finished seems right for a horror story; such stories are usually intended to shake up an audience at least a little, reminding readers that some aspects of life remain truly mysterious, even in a scientifically enlightened age.