Sting, White Dragon Slayer

Vigilance, Exalted, Protection from White, Protection from Dragons.
{2}{w}, {t}; Sting, White Dragon Slayer gains First Strike until end of turn.
If you control no creatures, you may cast Sting, White Dragon Slayer as though he had Flash.
Sacrifice a White permanent: Regenerate Sting, White Dragon Slayer.