They don't come much more rare than this baby-- you had 10 hours to get it, and the overwhelming odds are that you didn't anyway.

Name: Black Qiraji Resonating Crystal
Type: Legendary Ground Mount
Speed: 100%
Abilities:

• Well technically, the crystal isn't the mount-- it just summons one. It's the bug looking thing you see above.
• It's called a Silithid Scarab, or more formally, a Black Qiraji Battle Tank.
• Can be ridden anywhere in the world. More on why that's so special in a second.
• And while this may be a "bug" (get it?), players are reporting that there's something special about the way this mount is summoned-- while you do have to be out of combat and unmounted to actually summon it (like all mounts), you don't have to be either when you start summoning it (unlike other mounts). So you could be in combat (like, in a battleground), start to summon the mount, and as long as you've left combat by the time it finished, you'll be mounted.

How to Get It: You can't. At least, most of you can't. Lots of people can get non-black bug mounts-- they drop pretty regularly in Ahn'Qiraj 40, and can only be used in that instance (and not in combat-- apparently the bugs are very skittish).

But the black qiraji mounts are very, very rare, and the reason is this: they were given only to players who hit the gong outside of Ahn'Qiraj only during a 10-hour period after the opening of the gates.

So here's how to get one. First of all, if you're on a server where the gates have been open for more than 10 hours (which is most of them), you're out of luck. So you'll have to roll a toon on one of the newer servers-- yes, there are still quite a few servers out there who have not yet opened the AQ gates.

Then, of course, you'll have to get your character all the way up to 60, so you can start the questline that will give you the mallet you need to bang the gong to open the gates. In order to actually finish this questline, however, (which starts in Silithus, if you really want to try), you'll have to go all over Azeroth and do all kinds of super heroic stuff-- in short, you'll need to be backed by a guild full of people who know what they're doing. Oh, and then there's the whole "War Effort" thing. If you were playing back when AQ first came out, you'll remember that opening the gates requires the whole server-- Horde and Alliance-- to collect tons and tons of items for "the War Effort."

But after all that is finished (all in a day's work, right?), you can finally take your Scepter of Ahn'Qiraj down to the gates of AQ, hit the gong, and this black bug mount is yours. Oh, and if you're not the first to open the gates, you can still get the mount, you just have to hit the gong (which means you need to finish the quest also) sometime within 10 hours of when it is first hit. See why the mount is so rare?

Getting Rid of It: You're joking, right? Vendors won't even accept this thing from you.