Haze Dragon is one of the three skins released under the Royal Pack part of the House of Dragons offer. It could be purchased as part of an item deal in late September 2017.
Haze Dragon could be purchased for $9.99 in a limited time deal that included 16000 coins. It was not available for individual purchase and may not be available for purchase in the future.
Details of this skin may vary depending on location, platform or time.
Note: The Royal Pack sub-offer was released again for a limited time in late May 2019. This time the price for Haze Dragon and the 16000 coins was lowered to $4.99.