Creatures with Melt Armor take Direct DMG equal to 300 if they cast Frost Armor, Maji Shield, Block, Immunity, Reflect or Stoneskin. No Rage will be generated for the additional damage dealt. In addition, when a creature inflicted with Melt Armor Dies, All the enemy creatures will take 150 direct damage also. This ability will continue to stack with itself until cleansed.
For some reason Rampart is unlisted but also procs Melt Armor's damage effect.