something in gaseous form - how does one hurt it?

[Mistwell]

It's hard to kill a vampire already in gaseous form and at 0 hp. We did it by sealing one in a stone-shape spell to prevent it from getting back to it's coffin. There are other ways, but it certainly is a challenge.

 

[tylermalan]

It's basically for sneaking around and getting past barriers, not fighting.

Or if you want to be silent, yet still deadly.

 

[lukelightning]

It's hard to kill a vampire already in gaseous form and at 0 hp. We did it by sealing one in a stone-shape spell to prevent it from getting back to it's coffin. There are other ways, but it certainly is a challenge.

Windwall could work, or Otiluke's Resilient Sphere. Heck, trap the vampire in a telekinetic sphere then bring it outside into the sun.

Back in first edition gaseous form wouldn't work on your equipment. Instead of being a useful dungeon exploration tool, potions of gaseous form became our favorite "poisons." The DM stuck us with some annoying DMPC..we got him to drink the potion and *poof* he turns gaseous and all his items fell to the ground. Loot!

 

[marune]

or psionics.

Yeah, I learned it the hard way in my last campaign :

Try to get rif of a Invisible, Silent, Wind walked psionic !

(Well it ended when the undead beholder was released)