G0-R41-0N Ultratonk
Source: Drop. The next level of scrapbot technology: pushes the scrap into a heap, then destroys it with flame vents and rockets. Mechanical type. It spells out "GO-RAI-ON" which is a reference to the 1981-82 anime Beast King GoLion.
G0-R41-0N Ultratonk is a pet that drops from Mimiron in the Ulduar raid, obtainable via the 
Overcomplicated Controller.
Guide awaiting review
Defeat Mimiron in Ulduar
Enter the Ulduar raid and defeat Mimiron. The pet's summoning item drops from the chest after defeating him in 10-player mode.
Loot the Overcomplicated Controller
Open the chest that appears after Mimiron's defeat and retrieve the Overcomplicated Controller, which summons the pet.
Use the summoning item
Use the Overcomplicated Controller to summon G0-R41-0N Ultratonk as your battle pet.
