The Ring Of Self-Invisibility
Makes you invisible to yourself and only yourself.
(possibly useful to those with their heads up their asses)
tracer: No, you have to save vs. petrification (being stoned).
Is that anywhere near the Elemental Planes of Fermented Beverages, Back Support Devices, or Hot Fudge and Marshmallows?
I suspect your DM played Fallout 2, as there is a Kama Sutra Master perk (basically the same as a feat) and a drug called Jet which is very similar to krank.
You’re probably right about the KSM feat, but the guy playing the elf is the one that came up with krank (in the middle of play) and the DM just rolled with it. I’m pretty sure Elf-Guy isn’t a Fallout fan. The krank problem is a pretty natural extension of the social structure of our campaign.
There have been several items that I’ve thought were useful, but this one is probably the most exploitable.
You really should’ve mentioned how much electricity, poison gas, acid and vacuum you need to be exposed to in order for the effect to be triggered. Otherwise you’re going to have adventurers carrying around this scarab and, say, a homemade lemon battery, some highly diluted acid and a test tube of methane. 
Yeah, but where are they gonna get the Vacuum? Hoover and Electrolux weren’t around in the middle ages!
Teleport the air out of a sealed tube?
But, heck, if you’re going to waste a 5th-level teleport spell, you can afford to cast protection from fire.
Well, you could try to substitute a general sort of suction. Just turn to the seven foot tall swordswoman in the chainmail bikini standing next to you, idly counting dragon claws on her necklace, and blurt out “I need you to suck on me right now!”
I can guarantee that you will not be having a problem with the fire.