Does a poison 'pad' exist that I can wear in my palm, shake someone elses hand, then they die actually exist

In general, it's surprisingly difficult — compared to what's depicted in fiction — to poison a person to death. There are plenty of things out there in the world that are bad for people, but relatively few of them are downright toxic enough to kill. Of those, relatively few are toxic enough to kill in small doses. And of those, only a tiny number can be absorbed through the skin. Finding a substance that checks off all three boxes at once — deadly, potent and absorbed through the skin as opposed to having to be ingested or inhaled — narrows the field a lot … and the few substances that do fit all three criteria are not subtle.

For instance, one of the most potent toxins known is dimethylmercury, which is an organic compound that contains, obviously, mercury. In the 1990s there was a now-infamous case of a researcher specializing in organometallic toxins named Wetterhahn who allowed just a drop of dimethylmercury to touch her gloved hand, and it killed her.

But here's the thing: Her health gradually declined over ten months before she finally died, and the cause of her declining health was blindingly obvious: the levels of mercury in her blood and urine were many times higher than what's known to be toxic. An examination of her hair revealed exactly when she was exposed to the toxin and how much of it she was exposed to. If she'd been poisoned deliberately instead of accidentally, there would've been a mountain of evidence pointing to when, where and how it'd happened.

So in general, the answer to your question is no. To poison a person in that way — a single, massively toxic dose delivered transdermally — leaves a lot of evidence, making it effectively useless for clandestine sneaky-sneaks.

And that's before we even consider the question of how a person so armed would avoid contaminating everything he touched, including himself and all his co-conspirators.

All things considered, a car bomb is a lot easier and more reliable.

/r/NoStupidQuestions Thread