The Phantom of Vasquez Castle is the main antagonist of the Scooby-Doo, Where Are You episode, Hassle in the Castle.
In Hassle in The Castle, he was the disguise of ex-magician Bluestone the Great who was trying to find some buried treasue.
Scooby-Doo! Night of 100 Frights
In Scooby-Doo! Night of 100 Frights, The phantom was a common villain, brought back by the Mastermind and is featured in all areas (Mystic Manor, the Haunted Grounds and Smuggler's Cove). It was one of the few villains capable of flying/floating around. The ghost was unusual in that it's the only villain in the game that couldn't be killed. He is even in the Redbeard boss fight.
Scoboy-Doo! Mystery Mayhem
In Scooby-Doo! Mystey Mayhem, Walter Peabody's ghost costume was similar to the phantom.
Scooby-Doo! Moon Monster Madness
The Phantom appeared in the opening credits of Scooby-Doo! Moon Monster Madness.
Scooby-Doo! and Kiss: Rock and Roll Mystery
The Phantom appeared in Scooby-Doo! and Kiss: Rock and Roll Mystery as a hologram.
LEGO Scooby-Doo! Knight Time Terror
The Phantom recently appeared in LEGO Scooby-Doo! Knight Time Terror where his costume was worn by Kyle Grimsley.
The Ghost in the LEGO Scooby-Doo Mystery Mansion set is based on the Phantom.