The Black Qiraji Resonating Crystal summons a Black Qiraji Battle Tank, a legendary mount. As of Wrath of the Lich King, it was the only legendary mount to have ever been added to the game for players. The Crystal is a quest reward from  which requires the player to use the Scepter of the Shifting Sands on the gong on the Scarab Dais during the 10 hour battle with the Silithids which occurs during the opening of Ahn'Qiraj. This is a one time server event.
- This Crystal summons a swift, ridable Scarab that can be ridden when outside of the Temple of Ahn'Qiraj.
- Should other players possess the scepter, they may also receive the mount if they activate the gong up to 10 hours after the opening.
- This mount has the same riding speed as normal epic mounts.
- Because of the mount's dual purpose (usable both inside the Temple, where normal mounts formerly could not be used, and outside), it has never had the exact same casting behavior as a normal mount.
- There is currently only one other legendary mount, the GM flying mount .
Patches and hotfixes
- Patch 3.0.3 (04-Nov-2008): Converted into a normal mount, which removed one of its unique features - the ability to start summoning the mount while still in combat as long as the player was out of combat at the completion of the summon.
- Patch 2.2.0 (25-Sep-2007): Before this patch: unlike normal mounts, one could cast it while falling and mount up mid-air. (Though, if you landed while casting and took damage it interrupted the cast). Additionally, you could "insta switch" to the scarab mount while flying or running with another mount.
- Patch 1.9.0 (03-Jan-2006): Added
On February 6, 2009, sometime after Patch 3.0.8a, Bornakk posted on the forums that the Ahn'Qiraj gates will automatically be open on all new future realms. He would also later clarify in the thread that there are no plans to have an alternative method to obtain the Black Qiraji Battle Tank.
The final step of closure came with the release of Patch 3.2. The commendation officers in all major cities where removed and replaced with mailboxes.
If a player was logged out while mounted on this mount when patch 2.2 was deployed, upon logging in after the patch, the mount "buff" was replaced by a buff that transformed the player into a flying wasp. This was a one time occurrence, however, as there is no evidence the flying wasp buff is obtainable by any other means. However, a buff like it is available from Underbelly Elixir, possibly inspired by this bug.
During the Patch 3.0.2 PTR, the Black Qiraji Resonating Crystal had a changed tooltip which was roughly "This mount changes depending on your Riding skill and location." Upon testing this in several locations, it was found that the mount became a wasp in any zone you could fly in and the regular scarab in other zones. This functionality was removed before the patch was released.