Napoleon kill

(noun) Predicting something will end badly. Alternatively, a person who is thinking something will end badly. Similar to a buzz kill.

The origin is a pun on the name the famous American personal-success author Napoleon Hill ("Think and Grow Rich"). One of Mr. Hill's biggest beliefs was that ideas can become reality and for this reason you should try to eliminate all bad or critical thinking from your thoughts.

Him: "Dude, I'd buy an iPad, but all I'll end up doing is dropping it."

Her: "You're such a Napoleon kill!"