Fentonium is a frictionless synthetic crystal invented by Fenton Crackshell-Cabrera and completed with some help from Gandra Dee to make it stable to use. Once it starts bouncing, it keeps gaining energy and speeding up, rather than slowing down. This makes it 'an innovative energy generator from a mild-mannered source' according to Fenton. Fentonium appeared in the DuckTales (2017) episode, The Dangerous Chemistry of Gandra Dee! where it was used to defeat Mega Beaks.