This stuff is called the type H toxin and an injection of 2 billionths of a gram would kill an adult.
The substance is a form of the botulinum toxin, already the most deadly toxin on the planet.
"This new toxin, H, cannot be neutralized by any of the currently available antibotulinum antisera, which means that we have no effective treatment for this form of botulism," one of the researchers wrote.