Once a normal human, Cyanide was transformed by the reality-warping mutant, Mad Jim Jaspers. He then began working for the R.C.X. and trained to be one of their super powered operatives. Eventually, he and the R.X.C. came into conflict with Excalibur.
His power has the effect of poison, and by a single touch a person could be knocked off. It’s not known if he can also kill with his power.