From Destinypedia, the Destiny wiki
These Minotaurs are seen as the first bosses of both the Gauntlet and Crystals encounters, where they attempt to inhibit the Guardian Fireteam's progress through the Menagerie. They are to be killed in order to progress through the encounters (such as spawning new Crystals or beginning the run through the Gauntlet), and gather points. They will remain in their positions (atop the middle altar in the Gauntlet or at the top of the stairs in the Crystals), where they will lay into the team with their Torch Hammer and use their Temporal Shockwave if any get too close.
List of appearances