Grubbis

Gnomeregan

Hall of Gears

Enter through the main portal and take the Hall of Gears branch before descending into the Launch Bay. Clear the event space before starting the tunnel demolition; Grubbis and Chomper arrive after the trogg waves. Stop at the Clean Zone for Sparklematic cleaning, then visit the Dormitory punchograph if carrying a yellow card for Data Rescue.

Grubbis

Elite HumanoidChomperElite Beast

The tunnel-demolition event ends with Grubbis and Chomper together, so the group must collect the pair without losing control of the last troggs.

Tank
Pick up both Grubbis and Chomper as they emerge from the tunnel; keep Chomper with Grubbis rather than letting the basilisk reach the healer during the change from waves to bosses.
Healer
Keep the event tank in reach as the final troggs give way to Grubbis and Chomper. Both bosses can be hitting that tank before the group has finished Chomper.
Damage
Focus Chomper first while the tank holds Grubbis. Finish the basilisk before switching to Grubbis instead of splitting damage between the pair.