What's biting somebody?
(informal) something that you say in order to ask why someone is in a bad mood What's biting her? She hasn't said a word all morning.
nail-biting
a nail-biting event or period of time makes you feel very nervous, usually because you are waiting for something important to happen (always before noun) The teams were very evenly matched and played a close game right up to the nail-biting finish.