Frostfell Blast (3.5e Invocation)
From D&D Wiki
|Greater; 7th; Eldritch Essence|
By tearing a microrift into the heart of the paraelemental plane of ice, this eldritch essence invocation allows you to change your eldritch blast into a frostfell blast that deals supernaturally cold damage. Since the frostfell blast rips through the planes, it affects ethereal and other incorporeal creatures as if it were a force effect.
Since you are tapping into the near absolute-zero temperatures at the core of the multiverse, even creatures from the frozen wastes are affected by a frostfell blast. As such, cold resistance offers no protection against the frostfell blast, while immunity to cold damage instead reduces the damage by half.