Deadly Defense...

[Masakan]

Does the damage double on critical hits? Answers probably no but you know I just need to make sure.

[AvatarVecna]

Is "Deadly Defense" a reference to some class ability? Without knowing what the context is, I can only assume you're asking for in general. So, in general, a critical deals double base damage plus double damage bonuses; bonus damage dice are not multiplied by the critical multiplier. Furthermore, if a weapon has a better than double critical multiplier, you instead multiply the damage by that number (instead of 2).

[ZamielVanWeber]

No. Good rule of thumb: dice are not mutiplied while flat numbers are.
Also, for future reference, questions like these are a good candidate for the RAW Q&A thread.

[Masakan]

ok yeah that's what i figured.

[BowStreetRunner]

Is "Deadly Defense" a reference to some class ability?
FYI this is a feat from Complete Scoundrel that adds 1d6 to damage under certain conditions. ZamielVanWeber is correct here that extra damage dice are never multiplied (http://www.d20srd.org/srd/combat/combatStatistics.htm#multiplyingDamage).