The Molten Boss is the final boss in Molten mode. It also appears as the second major boss in Hardcore mode.

Like most other major bosses, the Molten Boss moves very slowly, but it has an extremely high amount of health. It also has burn immunity, making it immune to burn damage. Additionally, as it is a boss enemy, it is immune to being frozen, slowed down by the Toxic Gunner and it is only slowed down by the Electroshocker and Warden instead of being stunned.
Grave digger's GF