Blizzard is going to add the MVP Black mount to the game with the next update, to celebrate their impressive performance in the Heroes of the Storm Spring Championship. This is not the first time that the developers are rewarding the victors of the championship with their personal mount. Previously, after Blizzcon, Cloud 9 was rewarded the same way. The mount is announced to cost 5$, and Blizzard says that a portion of the money gathered from the sales will go directly to the team to support them. Check out this link to know more details about the promotion event as well as the team members.