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". The Grundel easily gets a young boy named Alec (who had just gotten in trouble for messing with the Ecto-1) to fall under his influence. While Alec is at first nothing more than aggressive and willing to steal, his crimes become dangerous when he messes up the Ghostbusters' packs while at an assembly (causing them to nearly burn the whole gym down). After possessing Alec for a while, the Grundel then decides to target his brother Lee. The Grundel has Alec lure his brother to an old warehouse, upon entering Lee discovers that his brother has nearly completed his transformation into a Grundel. The Grundel then attempts to posses Lee, but Lee refuses to let him in. The Ghostbusters show up, yet they cannot attack the Grundel as he is linked to Alec and harming him would also harm the boy. Alec and the Grundel chase Lee in order to make him allow the Grundel in. When Lee falls through the floor and holds on for dear life, Alec says that only the Grundel can help him and that he must accept the Grundel in order for him to take his hand. Peter Venkman however convinces Alec to not let his brother fall and Alec helps his brother as Peter wrestles with the Grundel. With Alec helping his brother, his bond with the Grundel is broken and the Ghostbusters are able to successfully capture him.

This however would not be the end of the Grundel. Years later, 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 Ghostbuster, Kylie Griffin. Kylie and Roland 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. The Grundel was able to influence the nearby brother of Roland, Casey, to release him from the Containment unit. Immediately after his escape, the Grundel teamed up with Jack and went 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. Though she was unable to beat him, Roland came in and caught the Grundel in a proton stream, giving Kylie the time she needed to set the trap and re-capture the escaped ghost. With the Grundle recaptured, Jack was freed from his spell and is happily reunited with Kylie.

Powers
The Grundel's only real power appears to be his power of influence over a child's heart. When the Grundel gets a child to answer his call, he feeds the aggression in their heart and cause them to act like bad children. After a while of misbehaving, the Grundel's power grows and the child transforms into a Grundel. Although it usually takes time for the transformation to begin, in Extreme Ghostbusters, a child's face would instantly transform into a Grundel face while the rest of the body would change over time. This aside, the Grundal also has the ability to travel amongst the shadows, entering and leaving where ever they may be. The only other possible power he seems to possess is his influence to get kids to come out. Though this is probably a mere skill rather than a power. A number of children who fall under his influence act as though they are in a trance, though this may just be sleepiness as he usually tries to get them while they are asleep. However when Alec became a Grudel the original apparetnly told him how to blast fireballs from his fingers.

In terms of weakness, the Grundel only seems to be weak when he has no children under his influence. When a child starts to transform, he becomes linked with the child, which is something the Ghostbusters had to be careful of during their first encounter with him. If a child refuses to listen to him or starts to go against him, he is an open target to the Ghostbusters. The Grundel also (like many ghosts) seems to be able to warded off by light, though whether he is truly weak against it or just tries to avoid being spotted is unknown.