Did you know that Black Qiraji Battle Tank (Scarab Lord mount) was originally intended to fly by turning into a wasp but the idea was ultimately scrapped?
During the Burning Crusade Pre-Patch 2.2 and Wrath of the Lich King PTR, Black Qiraji Battle Tank would turn into a flying wasp and fly in both Outland and Northrend. Apparently, Blizzard has scrapped the idea both times and it never went live.
Below is a model of the Flying Black Qiraji Battle Tank wasp mount. Thanks to Reddit user Igusy for this interesting screenshot!