During the re-exploration of Darkshade Caverns, Shatasha is trapped by Grobull's magic, and the delvers which have come to explore the caverns must defeat it to progress.
Grobull the Transmuted begins the fight completely immune to damage, and, until defeated, will periodically spawn two groups made up of three small bull-netchlings on the north and south of his battle area, and a medium-sized netch. When each of these is felled, Grobull receives a shock from them, and when he is shocked enough times, he will become stunned and lose his damage immunity.
Grobull will also shock the tank delver and stun them, or use an area-of-effect lightning attack, mid-battle. It is recommended to use Dark Talons, Magma Armor and area-of-effect damage abilities to defeat Grobull.