Despite the efforts of the X-Men, Kukulcan returned to San Rico, where he activated the Solar Stone (a large gem set in the Feathered Serpent idol), which increased his powers.  He then set about restoring the Mayan pyramids to their former glory and and placing all those of Mayan descent under his control.  The X-Men traveled to San Rico and again confronted him.  In the course of the battle, Kukulcan inadvertently knockED the Feathered Serpent idol into a large chasm, causing his powers and essence to fade, leaving only El Tigre.

(Thor Annual#10) - Quetzalcoatl was sent to aid Thor and many other gods against the menace of Demogorge the God Eater, who had been raised from the dawn of time by Ahpuch and the death-gods of other pantheons.  Unable to affect the entity in battle, he was consumed with the death-gods as well as his allies but was freed when Thor caused a shift in the creature's palate. Becoming Atum once more, his true being, Demogorge released Quetzalcoatl as well as all of the other swallowed immortals.

(Marvel Universe: The End#5) - Alongside various Earth heroes, Abstractions, and other gods, Quetzalcoatl was summoned by the Living Tribunal to oppose the mad Titan Thanos, who had usurped true omnipotence in the Marvel Universe. 

COMMENTS: Created by Alan Zelenetz and Bob Hall

The Aztecs Gods and the Mayan Gods are considered to be the same race, and are titled under the Mexican Gods.  They are, however, distinct from the Incan Gods.

In the myth section of Quetzalcoatl's history, it is stated that a vengeful Tezcatlipoca "convinced the Aztecs to accept the Spanish Conquistador Hernando Cortez as the returning Quetzalcoatl."  This, of course, does not come from any historical documentation or scholarly reference; it is merely another of Will's wild suppositions.  Although an imaginative concept, in reality no divine intervention instigated what would become a systematic slaughter of millions of American Natives by European invaders.  Instead, the Aztec people made a grave mistake by believing that Cortez was Quetzalcoatl returned, which, as the myth history illustrates, was supposed to occur at some point.--Kyle

Gaea admitted in Thor I#301 that she had been Coatlique as well as Jord to the Asgardians and Aditi to the Hindus.  This makes Quetzalcoatl siblings with Thor (of the Scandinavian/Norse Gods), the Titans (of the Greco-Roman pantheon), and the Adityas (ancestors of the Hindu Gods).

In Aztec Myth, Quetzalcoatl was often referred to as The Feathered Serpent.  Makes me think he'd have an archaeopteryx as a pet.  Appropriately enough, there is a giant pteradactyl named for him. It is called Quetzalcoatlus.

In Conan the Barbarian I#65, Conan and Belit encountered a sorcerer known as Tezcatlipoca, who used a feathered serpent as a familiar.  This feathered serpent attacked Conan, who cut off its head.
As this story took place in 10,000 BC, it is uncertain what, if any, connection exists between these two beings and the Mexican Gods of later millennia, or if it is meant to refer to some other predecessor.  (See the discussion under Gods of the Hyborian era for further discussion.)
In addition, in Conan of the Isles, Metemhoc, a native of Antilla (settled by some of the survivors of ancient Atlantis), referred to Conan by the name, Kukulcan, as a form of praise.

I also vaguely remember some adventure with Doc Savage and the "Feathered Serpent."  I'm not sure whether these should be considered in-continuity, even though Doc Savage has crossed over with the MU at a few points.
         The Doc Savage story involving the Feathered Serpent occurred in the early issues, in an adaptation of the novel "The Man of Bronze". In the original novel, the real Quetzacoatl was not involved....it was just a criminal posing as his son (using advanced science) to mislead the superstitious. The Son of the Feathered Serpent was actually Don Rubio Gorro, your garden variety corrupt Latin America government figure
    --Per Degaton.

Per Degaton  points out, "Young Allies Comics #20 has a story entitled, 'The Crown of Quetzalcoatl!'"

Profile by William Uchtman and Snood.

Profile updated/edited by Kyle Sims

CLARIFICATIONS: If you want to get really technical, although Kukulcan possesses, transforms, and controls el Tigre in X-Men I#25, 26; Kukulcan himself is actually physically behind the scenes.  The transformed version of El Tigre is not the physical form of the god Kukulcan, but I think this gets down to splitting hairs.  Technically, by that standard, his first actual physical appearance is not until he appears as Quetzalcoatl in Thor I Annual#10.

Other Gods and Eternals have been mistaken for Kukulcan/Quetzalcoatl in the past, these include:

• Ajak, a Polar Eternal, who formerly guarded the City of the Space Gods, @ Eternals I#2
• Virako, a Polar Eternal and the father of Ikaris, @ Thor Annual#7
  --by the way, for all things Eternal, check out Encyclopaedia Olympianna