The Silver Phantom is a Stoker Class dragon released in December 16th, 2016. It can be purchased for 750 Gems (600 Gems for members).
From the How To Train your Dragon Wiki:
- "Silver Phantoms are the fastest ride-able flying dragons known to Vikings, even faster than the Windwalker. They can also fly at the highest altitude, so high the air starts to thin. They are "very, very rare and very, very dangerous". As per their name, Silver Phantoms are the color of "the purest silver".
- The Complete Book of Dragons notes that this rare species has a small amount of dimorphism amongst the genders: females sport a single horn sprouting from their muzzles. They also have excellent sight, hearing, and sense of smell. The Dragon Key at the back of The Complete Book of Dragons also indicates Silver Phantoms can produce electricity, and shoot lasers or missiles (unclear which).
- Silver Phantoms also produce a lovely, lethal fire."
For more information on Silver Phantoms, visit here.