Black Knight (What a Night for a Knight)

The Black Knight was a clad suit of black armour.

Physical Appearance
A traditional English large, black, empty suit of armour with red feathers on his helmet.

Powers and Abilities
Only comes alive on nights when the moon is full.

Season One
Shaggy and Scooby find a mysterious black knight that the kids return to the museum. When there, they discover the archeologist delivering the knight is missing, and the knight has come to life. Mystery Inc. managed to trap the Black Knight and discover that it was Jeremiah Wickles. (What A Night For A Knight)

Scooby-Doo 2: Monsters Unleashed
A haunted suit of amour was Mystery Inc.'s first and most memorable case. He is the second monster to be brought to life, along with the 10,000 Volt Ghost and sneaks into Old Man Wickles' manor to await Mystery Inc.'s arrival. He battles Daphne in the manor, using his ghostly sword. He later appears to battle Fred in a joust, riding a horse while Fred uses a motorbike. The Black Knight and 10,000 Volt Ghost then corner Fred and Daphne. Daphne uses some jumper cables to absorb all of the 10,000 Volt Ghost's electricity into the Black Knight, causing him to explode and be defeated, his charred head rolls across the ground and exclaims his mistake with "Oh, crap!". He was portrayed by Kevin Durand and voiced by Bob Papenbrook.

Scooby-Doo! Phantom of the Knight
In this PC game, the identity of the Black Knight varies from game to game. He is haunting the tourist castle Joust for Fun and has kidnapped the woman who plays the princess, Bernice.

Trivia

 * It is a mystery on whether the Black Knight Ghost is the first monster or not. The first monster that Mystery Inc. ever unmasked was the Green Goo Monster, who appeared in the first episode of A Pup Named Scooby-Doo (the prequel to the "Scooby-Doo, Where Are You?" show), A Bicycle Built for Boo!. However in Scooby Doo 2 they said that it's their first case (though it's probably judst a homage to the first episode). But in the Scooby Doo Where Are You episode Fred says it looks like they have another mystery on their hands. But since Scooby-Doo! The Mystery Begins (A film about the origin of Mystery Inc and how they met, got the Mystery Machine, etc) they said the first mystery was their principal controlling 2 ghosts in order to get stamp misprint was hidden within the time capsule. In the final scene, the gang, uncertain of what to do now, begin to go their separate ways. However, Velma tells the gang about "strange goings-on" at the museum she heard about, and they all agree to get on the case once again. (This is presumably the case of the Black-Knight Ghost, their very first case as Mystery Inc.)
 * The Black Knight made a cameo appearance in Hassle in the Castle, when Fred used a suit of armor in his plan to trap the ghost.
 * In a crossover with "Batman: The Brave and the Bold," the costume is seen along with those of other classic Scooby Doo villains.