Dragon

Hudson, Goliath, and Demona battle a dragon in the Gargoyles: The Dark Ages pitch. [1]

The Dragon is the subject of an oath used by both Iago and Demona. The exact nature of the Dragon is as yet unknown (though both Iago and Demona were once members of the Wyvern Clan, and a wyvern is a two-legged dragon). ("Possession", "Tyrants")

When the Commandos depart from Castle Wyvern, Hudson thinks at first that their helicopter is a dragon, before Lexington mentions it to be machine of sort. ("Awakening Part Two")

It is uncertain yet as to whether genuine dragons exist in the Gargoyles Universe, beyond the magically animated stone statue that King Arthur, Griff, and Macbeth fought in the Brooklyn Botanical Gardens. [2]