thief in the night

A person or thing that moves in a swift and secretive, stealthy, or surreptitious manner. The cancer spread through my lungs and into my bones like a thief in the night, giving me no chance of beating it.

Common Names:

Name	Pronounced	Usage
Vsevolod	FSYE-vah-laht (Russian)	Russian, Ukrainian, Medieval Slavic
Ihintza	-	Basque
Paula	['pɔ:lə]
Anaiah	-	Biblical, Biblical Hebrew
Tiedemann	-	German (Archaic)
Leyton	LAY-tən	English (Rare)