My biggest fear, and the worst thing that could happen to me, would be not seeing my children grow up.
Aside from that, waking up because a mouse runs over me in bed would also be horrible. So most nights, the family cat sleeps next to my bed. No, not IN it, he has so much hair that he wouldn't find it comfortable, but too warm. (No, no mouse has ever been even close to my bed, but still..)