Dragon Ogres (and Shaggoths) bathe in lightning to invigorate themselves and extend their lives. They are immune to all lightning-based attacks and spells, for example, Skaven warp-lightning attacks and certain Lore of Heavens spells, such as Storm of Cronos and Forked Lightning. If for whatever reason, models with this rule are targeted by a lightning-based attack, they suffer no effects and become frenzied (even if normally Immune to Psychology).