A group of outcast mutants in the Marvel Universe. They first appeared in Uncanny X-Men #169.

In the Marvel Universe, human mutation has reached a point where an offshoot of humanity known as homo superior has emerged. These mutants possess abilities and characteristics that make them different from the rest of mankind.

Where some of these mutations are benificial, others cause their bearer to become an outcast from the rest of society. Many of these outcast mutants gathered in the Alley, a series of tunnels beneath the island of Manhattan originally designed for use in case of a nuclear attack. These outcast mutants originally were gathered together by Callisto, a female mutant, with the help of Caliban, a mutant with the ability to detect other mutants. Callisto organized these outcasts in the Alley and dubbed them the Morlocks after the underground race in H.G. Wells novel The Time Machine.

Over the years, the Morlocks came into conflict with another group of mutants, Charles Xavier's X-Men, when Callisto kidnapped the X-Man Angel to act as her consort. The X-Men's leader Storm and Callisto fought for leadership of the Morlocks, which Storm won.

Later, the Morlocks again came into conflict with the X-Men when Kitty Pryde was nearly forced to wed the Morlock Caliban in payment for saving her teammate Colossus's life.

The Morlocks were later attacked and slain by a group of mutants organized by Nathaniel Essex, the mutant known as Mister Sinister. This so-called Mutant Massacre cost many of the Morlocks their lives, with a few being rescued by the future X-Man Gambit, who was involved with Sinister in the planning of the attack. Among those who Gambit saved was a young mutant named Sarah, who would later become known as Marrow.

Marrow and a group of other mutants returned to the Alley years later and began a campaign of terror, as they attacked the people above ground. Again, the X-Men intervened with Storm and Marrow fighting until Marrow was seemingly killed by Storm.

Other members of the Morlocks are:

Ape
Tar Baby
The Healer
The Piper
Masque
Leech
Skids
Annalee
Sunder
Blow-Hard
Erg
Plague