You know the funny part is that I've actually been rewarded with the Vex Mythoclast a grand total of 4 times from the Vault of Glass, and each time I've dismantled them. I dismantled a Gally once too, got it by pure happen stance from a Nightfall. And in PvP, prior to the Dark Below, my old Scout Rifle from the Crucible Quartermaster that had Explosive Rounds. That bugger easily ruined the day for many a Vex user in the Crucible. They'd go to take aim only to get an explosion in the face and their aim getting tossed around. Another textbook example of how the supposed "ultimate weapons" aren't all that ultimate.