It's a way to clear high-lvl lairs very fast, and with no risk (even for a lvl 50). Doing it as I type this.

Smokebomb makes you stealth but allows you to still use venomous ploy, so you can just sit there and AOE them all with poison DOT continously.
Yay.
Couple of notes - first, if it spawns a boss creature (grand tybis), it will continually break your stealth and kill you - this was my problem at first. Just try another lair and you'll be okay. Second, I put my venomous ploy on a macro - just hit smokebomb, hit the macro, wait until they're dead, then hit my dump macro and move on.