Freak waves also known as Rogue waves (Part 1)

Freak waves also known as rogue waves, monster waves, episodic waves, killer waves, extreme waves, and abnormal waves are relatively large and spontaneous surface waves that occur far out in open water, and are a threat even to large ships and ocean liners.

In oceanography, rogue waves are more precisely defined as waves whose height is more than twice the significant wave height, which is itself defined as the mean of the largest third of waves in a wave record. Therefore, rogue waves are not necessarily the biggest waves found on the water; they are, rather, unusually large waves for a given sea state. Rogue waves seem not to have a single distinct cause, but occur where physical factors such as high winds and strong currents cause waves to merge to create a single exceptionally large wave.

Few pictures of Freak waves. They are scary, no doubt: