Malevolent Dragons

Dragons are one of the most powerful creatures in the magical world, but some of them use magic for evil purposes and to take over the world. Some villains can also turn into dragons using dark magic or power based dragons.

The physical appearance of dragons in fiction (either villainous/heroic ones) are not always the same between one another. Broadly speaking, dragons can be divided into the following groups depending on their physical appearances or other traits that they possess:
 * Western Dragons are typically depicted as huge, fire-breathing, scaly and horned lizard-like creatures with leathery bat-like wings, four legs and a long muscular tail. It is sometimes shown with feathered wings, crests, fiery manes, ivory spikes running down their spines and various exotic colorations. A dragon's blood often has magical properties. The typical dragon protects a cavern or castle filled with gold and treasure and is often associated with a great hero who tries to slay it. Though a winged creature, the dragon is generally to be found in its underground lair, a cave that identifies it as an ancient creature of earth.
 * Asian Dragons are typically portrayed as long, scaled serpentine creatures with four legs. Traditionally, they symbolize potent and auspicious powers, particularly control over water, rainfall, hurricanes and floods and are also a symbols of power, strength and good luck. They have also an extended range of supernatural powers, changing size or form (most are able to take on a human shape), flying among the clouds or hiding in water, forming clouds, turning into water, changing color to blend in with their surroundings as an effective form of camouflage or glowing in the dark.
 * Lesser Drakes is something of a catchall category including lesser draconian beings such as wyverns, worms/wyrms, lindworms, etc. which are generally smaller and more animal-like in minds and behaviors. Though not entirely accurate to being called dragons, lesser drakes are often considered distant kin of typical western dragons. These also include wyverns commonly depicted as dragons lacking forelegs due to their wings and modified front legs.

Animation

 * Maleficent (Disney's Sleeping Beauty)
 * Queen Narcissa (Enchanted)
 * Hydra (Disney's Hercules)
 * Madam Mim (Disney's The Sword in the Stone)
 * How to Train Your Dragon
 * Red Death
 * Drago's Bewilderbeast
 * Deathgrippers

Literature

 * Smaug (Lord of the Rings series)
 * Hydra (Percy Jackson series)