A mutant was an individual, organism, or new genetic character arising or resulting from an instance of mutation, which is a sudden structural change within the DNA of a gene or chromosome of an organism resulting in the creation of a new character or trait not found in the parental type.
In some cases, mutants were created through genetic engineering, radiation or the dark side of the Force, most notably Sith alchemy and magic. Subjects were often remade into mutants to be more brutal, more cunning, and, in some cases, more intelligent, such as Wilk, a wolf from the forest moon of Endor who was able to understand and speak Galactic Basic Standard. In other cases, individuals of a wide range of species were born mutants most notably Triclops and the Keeramak.
- Battle hydra – Exar Kun
- Behemoth from the World Below – Seviss Vaa, New Sith
- Chrysalide rancors – Reborn Emperor Palpatine
- Gorc – Blackhole
- Imperial Sentinels – Reborn Emperor Palpatine
- Leviathans – Dark Jedi during the Hundred-Year Darkness
- Maraki – Kyrisa
- Massassi – Old Sith Empire
- Night Beast – Exar Kun
- Picaroon C. Boodle – Blackhole
- Rakghoul – Karness Muur/Muur Talisman
- Sea Leviathan - Vul Isen
- Sith war behemoth – Old Sith Empire
- Sith warbird – Old Sith Empire
- Sith war rhino – Old Sith Empire
- Sith war worm – Old Sith Empire
- Storm beast – Darth Revan's Sith Empire?
- Taanab mutant rancor – Disciples of Ragnos
- Technobeast – Dark Lord Belia Darzu
- Terentatek – Exar Kun
- Triclops – Palpatine
- Unkajo – Kyrisa
- Flesh Raider - Infinite Empire
- Keeramak - Ssi-ruuvi Imperium
- Mutant Nelvaanian warriors - Techno Union
- Vagh Rodiek - Yuuzhan Vong
- Voxyn - Yuuzhan Vong
- Darth Millennial
- Mutant acklay
- Mutant akk dog
- Mutant mynock
- Dark Empire Sourcebook
- The Essential Chronology
- The New Essential Chronology
- The New Essential Guide to Droids
- "Kyle Katarn's Tale, Mission 4: Showdown on the Sulon Star"
- The Jedi Academy Sourcebook
- The New Jedi Order Sourcebook
- Ultimate Adversaries
- The Starhoppers of Aduba-3"—Star Wars Gamer 4 "
- I, Yuuzhan Vong"—Star Wars Gamer 8 "
- "dossier BXLH: Les mutants dans Star Wars"—Graal 23
- The Essential Atlas