If an AI has any motivation at all, say, to make paperclips as efficiently as possible, then any threat to its existence is a threat to its objective function - namely, to create paperclips. A hyper-intelligent entity who is instructed to optimize for paperclips created will therefore proactively remove threats to its existence (i.e. its paperclip-creating functionality) and might possibly turn the entire solar system into paperclips within a few years if its objective function isn't carefully determined.