[D&D 3.5] Dealing elemental damage to same elemental subtype

[theonesin]

So, a bit of a derp on my part, but on the Frost Mage I built, I didn't forgot that the Piercing Cold feat doesn't let me bypass the cold immunity of creatures with the cold subtype.

So now, I'm trying to figure out ways to be able to do damage to these types of enemies(other than using different element types). I know the Lord of the Uttercold feat can turn it to half cold and have negative energy damage. Is there anything else that can help me?

[Chronos]

It won't help you if you're set on a frost mage, but the fire equivalent, Searing Spell, does work even on fire subtype creatures.

[Phelix-Mu]

I can't really think of a good reason why Piercing Cold and Searing Spell shouldn't be functionally equivalent. It's kind of bizarre and lame that they don't do the same thing, frankly, and one probably could make a decent argument to a given DM to houserule on the matter.

Looking at the RAW again, Piercing Cold's description is pretty complex for a fairly simple intention.