Evil Entity

"Soon... Soon I will be free! The time of Nibiru is nearly at hand. The planets are coming into alignment, working toward my release...as are you. Even though you know it not, I forged you. You are my proudest creation! So come now...Children of Nibiru! Be strong, and set your master free, so that I may bathe this world...in fire!"

- The imprisoned Evil Entity anticipating its release as Nibiru and Mystery Incorporated approach.

The Evil Entity is a recurring villian on the second season of Scooby Doo: Mystery, Inc. and the main antagonist of the show's final two epsiodes: Through the Curtian and Come Undone. It/He is an evil Anunnaki that wants to consume and destroy the world. It was imprisoned in what would eventually become the Cursed Treasure of Crystal Cove, but was released by Professor Pericles.

Past
Like other more benevolent members of its race, the Evil Entity came to Earth thousands of years ago at the time of the celestial event called Nibiru, when a planetary alignment weakened the barriers between dimensions and allowed the Anunnaki to cross over. While the other Anunnaki sought to help humankind grow, the Entity desired only to consume and destroy them and then the rest of the earthly universe. Its plans were discovered before it could take physical form in the Earth dimension in the manner typical of its race (by possessing a native animal), and so the other Anunnaki incapacitated and trapped the Entity in an inter-dimensional prison within a crystal sarcophagus.

Through means unknown, the sarcophagus imprisoning the Evil Entity wound up in the Yucatán, where the imprisoned Entity devised a plan to ensure its release. Using what little psychic power it was still able to exercise on the Earth, it subliminally brought together the Hunters of Secrets - a group of four humans and their pet jaguar - with the intent that they locate its sarcophagus and free it. The Hunters deduced the Entity's true nature and plans, however, and devised a means to destroy it using the Heart of the Jaguar, but as they were making preparations, the sarcophagus was stolen away by a band of Spanish conquistadors led by Fernando El Aguirre, who saw it as a valuable treasure; perhaps as the result of further manipulation by the Entity in order to save its own life.

The imprisoned Evil Entity's mere presence proved corruptive to the conquistadors, who succumbed to dark impulses; driven to destroy entire villages in search of riches. Deeming the sarcophagus cursed, El Aguirre and his men anchored in a cove on the North American coastline and took the sarcophagus and all the other treasure its influence had compelled them to plunder deep into catacombs beneath the bay, intending to hide them away forever. Using the mysterious, alchemical Planispheric Disk, they charted a path through caverns, and through time and space itself, sealing the sarcophagus and the Entity away in the space between dimensions, barring the way with a series of four elementally-locked interdimensional gates, and then splitting the disk into six pieces and scattering them to prevent the "Cursed Treasure" from ever being found again.

Although further sealed away, the Evil Entity's corruptive influence over the earthly reality remained strong, and its mere presence shaped the town that grew on the land above its resting place, dubbed "Crystal Cove" by the conquistadors for the dark secret it held. Under the Entity's sway, the town became a centre of the mysterious and weird, where people decided that the best way to commit crimes was to dress up as ghosts and monsters using increasingly outlandish and infeasible technology. But these mystery scenarios were but the catalyst for the Evil Entity's true plan: as it had done before with the Hunters of Secrets, it brought together mystery-solving groups who combatted these criminals and mysteries; consisting of four humans (whose mystery-solving abilities would allow them to discover the locations of the scattered pieces of the Planispheric Disk, and reach the cursed treasure and free the Evil Entity), and one animal (which the Entity could possess upon being freed, in order to take physical form on Earth). Unfortunately for the Entity, its corrupting touch also worked against it, as group after group fell victim to their dark sides, turning on each other and falling apart long before they could find all the disk pieces. The group that came the closest was the original Mystery Incorporated, whose maniacal mascot Professor Pericles actively sought to be possessed by the Evil Entity in order to gain its power, but they were forced out of Crystal Cove by Fred Jones, Sr..

Scooby-Doo! Mystery Incorporated
When the new Mystery Incorporated succeeded in locating all the disk pieces and reforming the Planispheric Disk, they were forced to hand the disc over to Pericles, who used it to unearth the elemental gates beneath Crystal Cove, and both Pericles and the new Mystery Incorporated subsequently raced through the gates across the dimensions, until they reached the fourth, fiery dimension holding the Cursed Treasure. As the solar celestial alignment of Nibiru came, Pericles released the Evil Entity from its prison within the sarcophagus. The Entity intended to possess Scooby-Doo, but when Scooby rejected it, Pericles offered himself up to the Entity as a willing vessel, evidently unaware that he would be entirely subsumed by the Entity upon possession. Taking Pericles's body, the Evil Entity gained physical form as a tentacled mass, and it immediately began releasing its evil Anunnaki servants, and they and the Entity began rising to and destroying Crystal Cove. There, with its servants' help, the Evil Entity began consuming the inhabitants of Crystal Cove, with the aim of growing strong enough to fully break free from its binding lifeline to the sarcophagus prison so it could move on to consume planets and galaxies and eventually the Earth's entire universe.

Discovering that they were mystically protected against the Evil Entity's touch when they stood together, the Mystery Incorporated kids realized that unlike the other mystery-solving groups forged by the Entity, their friendship was real, like the Hunters of Secrets before them, and in turn realized from this that their friendship was their weapon against the Entity. With this revelation, the kids worked together to get the Heart of the Jaguar past the evil Anunnaki minions to the Entity, until Scooby succeeded in plunging the Heart into the sarcophagus that had imprisoned the Entity. With the sarcophagus' destruction by the Heart of the Jaguar, the Evil Entity's lifeline link to its prison was severed before it was strong enough to fully break free. Crystal Cove, the evil Anunnaki and the Evil Entity were then sucked up, and the Entity was destroyed once and for all. The Entity's destruction undid all of its evil throughout time, creating an altered timeline in which all those whom the Entity's evil influence had negatively affected over history lived happy and contented lives.

Trivia

 * The Evil Entity is very similar to three other villains:
 * Satan/Lucifer: Both were aberrantly evil members of a race of normally-benevolent beings that had humanity's best interests at heart. They both also spent their time corrupting and tainting all those that came in contact with their influence. Lucifer and the Evil Entity were also both cast out, incapacitated and imprisoned by their benevolent kin after their original rise to evil, but would one day be freed and rise again to bring apocalyptic darkness and destruction and to end the world. Also, both Lucifer and the Evil Entity are the masters of armies of evil minions who were among other evil members of their kind.
 * Cthulhu: Both are ancient extradimensional/extraterrestrial beings that were released to destroy humanity when the right celestial alignment arrives, and their physical form has squid-like traits. Their influence causes morality to dissolve and causes bad dreams.
 * It: Both are ancient beings that, unlike most Eldritch Abominations, are not above good and evil by human standards. They hold an influence over the town they haunt, both eat people, and can only be killed by the protagonists when they are united in friendship. A slight difference is when the Evil Entity was killed, he was erased from existence and history; while when It was killed, Its influence disappeared as if It never existed only from the point in time onwards from Its death.
 * The Evil Entity changes size over the course of the final Mystery Incorporated episode Come Undone. Just after consuming and possessing Professor Pericles, the Entity was approximately three - four times the size of an average-sized man; but after it rose to Crystal Cove to begin feeding, the Entity was the size of a very large building. This may have been a production error, or it may have been due to the Entity's physical form expanding as it grew stronger and unleashed more of its full power.
 * The Evil Entity was voiced by Clancy Brown, who also did the voice of Hades from the God of War series, Mr. Krabs from SpongeBob SquarePants, Savage Opress from Star Wars: The Clone Wars, and Silas from Transformers Prime.
 * The Evil Entity is certanily condsidered to be the darkest Scooby-Doo villain ever.