Megonite moss

"There's absolutely a profit in megonite moss, but possession of the stuff is a class one felony."

- Platt Okeefe comments in the Smuggler's Guide

Megonite moss was a type of moss. When writing the book that would become known as the Smuggler's Guide, the former pirate Queen Maz Kanata listed it as one of the cargoes that offered the most profit per kilogram for smugglers, but warned that stable packaging of the moss was critical. When the smuggler Platt Okeefe came into possession of the book, she added a section that questioned Kanata's choice of recommending the moss, since while the cargo was profitable, it was also a class one felony to be in possession of it.

Behind the scenes
In the current canon, megonite moss was first mentioned in Star Wars: Smuggler's Guide, a reference book written by Daniel Wallace and released in 2018. The moss originated in the Star Wars Legends continuity, where it first appeared in the 1979 comic strip Princess Leia, Imperial Servant, which was written by Russ Helm and described megonite moss as a highly explosive substance.