Mercury Dragon

Mercury dragons were whimsical, impulsive metallic dragons that delighted in unpredictability and were reputed to be mentally unstable as well.
Mercury dragons had sleek and serpentine bodies with a whip-like tail, lacking the muscular bulk other dragon races had. They had sleek heads with a long, pointed snout, and with horns curving backward from behind their jaws and eyes.
Mercury dragons were quick and agile flyers, and they had smooth, flat, barely discernible silver-white scales that seem to flow together as one. While at birth their scales were dull silver in hue, as a mercury dragon got older its scales became brighter, until they became as brilliant as a mirror. Likewise, their eyes were deep blue or violet with a dark pupil and a pale yellow-white iris in their younger years, but as they got older, their pupils became paler and brighter, their eyes resembling silver orbs.
While mercury dragons had no venomous attacks, their breath weapons and flesh were highly poisonous.
Personality Much as their name suggested, mercury dragons had mercurial personalities. Their mood shifted from time to time,[4] and they rarely finished a thought before moving on to the next thing that came to mind.[2] An individual mercury dragon acted depending on its recent experiences. Mercury dragons that were bored or puzzled usually attacked without any provocation, while those who had experienced a lot of events were more open to talk to their adversaries instead of fighting. They usually were more cunning if they were in a disadvantageous circumstance.
Mercury dragons craved to live new experiences. Because of that, they liked to shapechange into humanoid form to experiment with new circumstances. While mercury dragons didn't understand the psychology of the humanoid's life, and usually had eccentric personalities while shapechanged, the older the mercury dragon was, the more circumspect its personality became while in humanoid form.
Their craving for new experiences extended to their diet preferences as well. Mercury dragons had to eat something different each day, as if a mercury dragon was forced to eat the same food each day, it quickly became listless and hard to awake from sleep.
Treasure A mercury dragon's hoard was a hodgepodge of coins, jewelry, and items from scores of lands and dozens of eras, as mercury dragons weren't good at assembling matched sets or cohesive collections. They were often willing to exchange something from their hoards for some items they had heard about but never seen, especially when they were trading away a duplicate.
Combat Mercury dragons were as unpredictable in combat as they were in any other situation. They usually used weird strategies such as fleeing rather than fighting a battle they'd started, talking to their adversaries while fighting, playing a cat-and-mouse game with hostile pursuers, and so on. If opponents pursued it, a mercury dragon preferred to use its superior maneuverability and speed to outmaneuver its foes, launching a series of hit-and-run attacks from the direction of the sun.
Breath weapon Mercury dragons could breathe a line of intense light that burned whatever it touched. The magic of its breath weapon was poisonous, rendering a mercury dragon invisible to its victims. Mercury dragons usually boasted while hidden after using their breath weapons.
Abilities Mercury dragons had the ability to turn into a liquid quicksilver form, allowing them to move across any kind of terrain. They also were immune to any effects that affected their sight.
They also had the ability to cast both arcane and divine spells.
Society Mercury dragons usually liked to enter into working arrangements with any creature that seemed stronger or smarter than them, and often with creatures that could travel between the Elemental Chaos and the natural world. Such arrangements were usually feudal in nature, with the dragon agreeing to serve as a guardian, messenger, or hired killer in exchange for some combination of lair space, treasure, food, and the promise of varied experience. Those arrangements only lasted as long as the master could maintain the mercury dragon's interest, however, and a mercury dragon usually ended the contract just to see what would happen.
Lairs Mercury dragons liked to lair in warm, volcanic ranges and tropical regions, preferring to dwell near snowfields, glaciers, mountain lakes, sun-dappled alpine meadows, and places that had portals to the Elemental Chaos, a place they liked because of its ever-changing nature. They made their lairs in lava tubes and other narrow, winding tunnels or high caves, preferring those that allowed them to enjoy clear air and bright sunlight, and their lairs usually faced east to catch the morning sun. However, few mercury dragons maintained a single lair for any length of time.