- "Morseerians are methane breathers."
- ―Has Obitt
Methane was a type of gas. The atmosphere of the planet Merj was made up of methane, meaning that the native Morseerian species evolved to breath methane instead of oxygen, and thus had to wear breath masks when on planets with oxygen-based atmospheres. The Skakoans also breathed methane. The clouds of the planet Bastatha were made of methane and sulfur.
- Catalyst: A Rogue One Novel
- Alphabet Squadron (Mentioned only)
- Aftermath: Life Debt (Mentioned only)
- Bloodline (First appearance)
- Star Wars: Absolutely Everything You Need to Know (First mentioned)
- Star Wars: Alien Archive
- Star Wars: How Not to Get Eaten by Ewoks and Other Galactic Survival Skills
- Star Wars: The Rise of Skywalker: The Visual Dictionary