Recently a question came up in my group as to whether it is flavor text when it states:
Mostly this question came up because we are fighting quite a few vampires and vampire spawn at the current time. We came to the conclusion that even though they turn into gas when they hit 0 hit points, they would still take the rest of the damage even though it doesn't really effect them.
Some of us think that it was written as intended to off-set the ability to destroy undead outright like you could in 3.5. The other people though think that it's just flavor text and should be taken as such.
Any ideas?