Lichen

Lichen was a type of fungus that grew in the caves of the icy planet Hoth. The fungus was able to grow due to the small amount of sunshine that filtered into the cave from the planet's surface. It was eaten by the many species of tauntaun native to the planet. Another type of lichen was found on Jeosyn. This species glowed softly. In 22 BBY, during a mission to the planet Thule, Jedi Knight Iskat Akaris saw clumps of slugs feeding on the rocky wall of a canyon and thought they looked similar to patches of lichen growing on a tree.

A poisonous type of lichen grew on the planet Parnassos. In 24 ABY, the warrior Phasma realized that it caused festering in the wounds of her clan, the Scyre. Crushing the lichen into a paste, she smeared it on her blades, using it to subdue Balder, the leader of the rival Claw clan.

Text and facts from the “Lichen” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.