The Grundel

The Grundel is a villain from the Ghostbusters cartoon series and is notable for being one of the few ghosts to ever appear in more than one episode - this gruesome bogeyman specialised in the particularly evil trade of corrupting children.

History
The Grundel makes his debut in the episode titled "The Grundel", where he easily gets a young boy named Alec (who had just gotten in trouble for messing with the Ecto-1) to fall under his influence. After possessing Alec for a while, the Grundel decides to target his brother Lee. To that end, he has Alec lure Lee to an old warehouse, but the Ghostbusters show up to the scene, yet they cannot attack the Grundel as he's still possessing Alec. Eventually, Peter convinces Alec to rebel against the Grundel to save Lee from falling, to which Alec does, much to the Grundel's anger. With Alec's act of kindess, his bond with the Grundel is broken and the Ghostbusters are able to successfully capture him. This however would not be the end as a second Grundel appeared and started following in the footsteps of the first. This Grundel turned out to be a boy named Jack, an old friend of Kylie Griffin. Upon hearing about the second Grundel attack, Kylie interrogated the first Grundel about what happened with Jack and learned from the Grundel that Jack had not diverted back to his original form due to a special cocoon he was kept in. Eventually the first Grundel escaped and teamed up with Jack to go after Casey in an attempt to trap Kylie. The Ghostbusters got there just as Casey had transformed. While the rest of the team went after Jack and Casey, Kylie stayed behind and faced the first Grundel herself. Fortunately, Roland came in and caught the Grundel in a proton stream, giving Kylie enough time to set the trap and re-capture the escaped ghost. With the Grundle captured once again, Jack was freed from his control and is happily reunited with Kylie.

Trivia

 * In his first appearance, the Grundel mutters something about "finding another" when he first manifests, suggesting that he was not a Grundel originally and instead was a child turned into one. However, he also may have been referring to a previous child he managed to manipulate.
 * The Grundel was the only villain from the original Ghostbuster series to return in an actual episode of the Extreme Ghosbusters (though such villains as Samhain and Ghash did make cameos in the opening theme song and the Boogieman was mentioned in one episode).
 * The online multiplayer missions of Ghostbusters: The Video Game feature a Most Wanted Ghost also named The Grundel.