Merlock the Magician

Merlock is a sorcerer and the main antagonist of DuckTales the Movie: Treasure of the Lost Lamp, voiced by actor Christopher Lloyd.
 * quote = "Who's there?!"

Background
Merlock is an anthropomorphic wolf. He possesses a green magic talisman that gives him magic powers, which include the ability to transform into (non-anthropomorphic) animals, including a hawk, a beetle, a gryphon, a bear, and a mountain lion. When placed on the Genie's magic lamp, the talisman grants Merlock an unlimited number of wishes to be granted, instead of the usual three.

At some point in the past, Merlock was the Genie's master, and was granted immortality as his first wish. When he had possessed the lamp, some of the sorcerer's wishes that were unwillingly granted by the Genie included his own immortality, the destruction of Atlantis (which, in this case, was not a city but a luxury resort - and Merlock couldn't get a reservation), the eruption of Mount Vesuvius that wiped out Pompeii, and the creation of anchovy pizza.

DuckTales the Movie: Treasure of the Lost Lamp
In DuckTales the Movie: Treasure of the Lost Lamp, Merlock (a portmanteau of Merlin and warlock) is obsessed with retrieving the Genie's lamp, which he apparently lost to the thief Collie Baba (a parody of Ali Baba) centuries before.

Collie Baba buried the lamp, along with a large amount of treasure, in the middle of a desert. To this end, he hired Dijon to steal the lamp. Dijon is later hired as a guide to Scrooge McDuck, who is searching for the treasure. The lamp ends up in the hands of Webby Vanderquack. When Dijon fails to steal the lamp, Merlock becomes angry and attempts to trap the group. Luckily, Scrooge and the others are able to escape.

Near the end of the film, Merlock is able to take the lamp for himself, and forces the Genie to grant his wishes. Merlock has the Genie turn Scrooge's money bin into a recreation of his old floating fortress, and later tries to have Scrooge destroyed. Scrooge is able to take Merlock with him, and engages in an aerial battle with the sorcerer. Eventually, Scrooge is able to regain the lamp and turn everything back to normal. Merlock loses his talisman during the flight, resulting in the loss of his powers. Merlock is last seen falling to his death.

Legend of Illusion
Merlock's next appearance was in the video game Legend of Illusion starring Mickey Mouse, in which he is known as the Sorcerer of Darkness and is responsible for stopping the River of Time and threatening the Tree of Life in the process. Mickey Mouse must defeat Merlock in order to restore everything to what it once was. He mainly uses fire and lightning to attack. Eventually, he'll change into a dragon, changing his strategy entirely. He will breath fire at Mickey, fly to the other side of the screen, and toss a spiked ball in front of him.

Donald Duck: Goin' Quackers
Merlock also appears in the video game Donald Duck: Goin' Quackers as the main antagonist (whether this indicates he survives the events of the film is unknown). He captures reporter Daisy Duck after she infiltrates his temple, and Donald Duck sets out to rescue her. In the final level movie, Donald Duck reaches Merlock's lair, and the final battle between him and Merlock begins. Merlock has three attacks. The first one is to make the floor tiles disappear. Second, to unleash arrows, and the third is the fire attack. In the end, Donald rescues Daisy.