Dark Horse

One who was previously unknown and is now prominent.



This was originally horse racing parlance. A dark horse was one that wasn't known to the punters and was difficult to place odds on. The figurative use later spread to other fields and has come to apply to anyone who comes under scrutiny but is previously little known.

Ex: This guy is the dark horse of the of the competition so don’t be surprised if he comes up with something special



Spanish: incógnita



German: stilles Wasser

