In the 1900s, Doctor Kruger lived in a Brownstone in Yorkville, New York and conducted fear-based experiments aimed at learning how people process fear. Some viewed his work as crazy and thought his experiments were more like torture. Things became so bad that Kruger became known as Schreckgespenst or "Bogeyman."   After Kruger died in residence, the city sealed the building. Decades later, it was finally sold and reopened but there were consistent reports of various forms of paranormal activity. Kruger's ghost was sealed within the building and couldn't leave.   Kruger's ghost used the ghost of one of his victims, Timothy, to lure people into the Brownstone. Some time after the resolution of the dimensional bleed incident, the Ghostbusters were called to the Brownstone. Patty Tolan couldn't shake a feeling she knew about the place. Abby Yates picked up a reading on her P.K.E. Meter. They were surprised by Timothy but used the Hi-Lo maneuver to trap him. They failed to notice Abby was possessed by Kruger nor did they see her destroy her P.K.E. Meter. They left and inadvertently freed Kruger.
After returning to the Firehouse, Patty found a entry about the Brownstone and informed Jillian Holtzmann and Erin Gilbert. They all soon realized Kruger possessed Abby. Kruger was delighted his plan worked and he hadn't lost his touch after so long. Abby soon vomited ectoplasm all over. Holtzmann used a new invention called the De-Possessor to separate Kruger and Abby from each other. Kruger counterattacked and drained the ladies. He thanked them for boost and deemed he was ready to implement phase two. Abby cleared Holtzmann to use one of her untested inventions to take out Kruger. However, he escaped from the Ghost Zamboni and burst through the upper floors then flew to the Empire State Building. Luckily, Erin got insurance to cover the damage. They ran to the roof, considered the implications of what Kruger could do to the city and spotted him.
After watching the 10:21 am news update, Abby wanted to confront him again instead of doing nothing and letting him take over the city. Patty disagreed and proposed they do some research, make a new weapon, and come up with a sound plan. Holtzmann like the idea of a new weapon but she needed to observe Kruger in order to think of something that would be effective against him even though they would get their butts kicked again in the process. They arrived at the Empire State Building after a 39 minute drive. They switched their packs to full power then headed into the lobby. Kruger was amused they came and found it ambitious and naively optimistic. They opened fire and wrangled him but he was being powered by multiple streams of an unidentified energy. Kruger clothes-lined them with thick extended fingernails and sent them into individual fear dimensions. while their bodies lay on the floor of the lobby in a catatonic state. He exploited their fears: Abby's fear of clowns, Patty's fear of abandonment and dolls, Erin's fear of not being accepted and of bees, and Holtzmann's fear of corporate bureaucracy and useless hands. Kruger reveled in the Ghostbusters' fears but also continued working on trapping them inside their nightmares forever then repeat the same with the entire city.
40 minutes later, the Ghostbusters sulked at Betty's Diner in Midtown Manhattan. After Erin admitted to her fear of bees, Holtzmann realized the specificity of the fears was the source of their defeat and went back to work on a new device. Abby, Erin, and Patty returned to Kruger's Brownstone in search of his underground lab in hopes of finding out how he was able to feed off fear and create living nightmares. They followed the brownstone's schematics to where the lab entrance was located and found a wall. Abby suddenly charged the wall with an axe and chopped away. They spread out and searched the lab for records or files on Kruger's experiments, careful not to disturb anything and alert anymore bound ghosts. Patty found a large book off the third shelf and realized it was his journal. Erin disturbed something and about a dozen of Kruger's Victims manifested. Patty knew one was behind her and ran for the stairs. They trapped the ghosts then returned to the Firehouse. Erin thought it was a good idea to call Mayor Bradley and get the brownstone condemned. Patty kept reading the journal and figured out what Kruger was planning. Holtzmann introduced her Dream Machine to the others upon their return. After several hours, Kruger drew in a steady stream of nightmares from all over New York City and was ready to merge the Nightmare-Scape with the real world. He planned to become the god of that new world. The Ghostbusters returned but Kruger believed nothing could stop him.
The team confronted Kruger and he grabbed them with his tendrils again. They entered the Nightmare-Scape again but, this time, with their Dream Machine technology activated. They were still separated but focused on their shared memory of St. Paul's Chapel. Kruger found Erin, Abby, and Patty in the chapel. He admitted using a shared memory was clever but they couldn't hide from him. Erin corrected him and stated their plan was to lure him to the chapel. They opened fire on Kruger but struggled to hold on. Holtzmann joined the battle. Kruger tried to shrug off their effort but with no fear to feed on from the united team, he was weakened. They were blown back to the real world. Kruger refused to give up and pointed he was only defeated on the Nightmare-Scape and in the real world, he could tap into dreams of others and regain his energy then boost himself even further. Kruger mocked them for forgetting they would be too weak to fight back upon exiting the Nightmare-Scape. They already planned for that outcome. Kevin Beckman ambushed Kruger with his own Proton Pack and captured him with a JH Modified Trap. Another version of Doctor Kruger appeared among Connla's Army in the prime dimension.
Kruger displayed standard abilities of flight and possession. He could manipulate a lesser entity, a Class 3, to manifest. He has a unique ability to feed on fears and increase his own power and to transport a victim's consciousness into the Nightmare-Scape.
- Schreckgespenst is one of many names for the Bogeyman in legend. It is German in origin.
- On page 9 of Ghostbusters: Answer The Call Issue #1, Holtzmann's reaction to Kruger's name is an allusion to Freddy Krueger of the Nightmare on Elm Street movie franchise.
- On page 13 of Ghostbusters: Answer The Call Issue #5, Holtzmann notes Kruger had a similar name to Hans Gruber, the villain from "Die Hard" after she quoted McClane's catch phrase.
- Ghostbusters: Answer The Call
- Ghostbusters Annual 2018
- Patty Tolan (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #1" (2017) (Comic p.9). Patty Tolan says: "A Doctor Kruger."
- Patty Tolan (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #1" (2017) (Comic p.10). Patty Tolan says: "Anyway, it was so bad that he became known as... Schreckgespenst."
- Patty Tolan (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #1" (2017) (Comic p.9). Patty Tolan says: "Yes, but that's not the important part, that's not what landed it on the map. Some kind of mad scientist doctor guy lived there in the 1900s."
- Patty Tolan (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #1" (2017) (Comic p.9). Patty Tolan says: "He did crazy experiments on people. Some called it torture. Some kind of fear-based experiments - something about learning how people process fear."
- Patty Tolan (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #1" (2017) (Comic p.11). Patty Tolan says: "This place was so bad, that after he died in residence, naturally -- the city just sealed it up. It was only sold and reopened decades later. And they've had consistent reports of paranormal activity -- in a variety of colorful flavors, ever since."
- Doctor Kruger (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #1" (2017) (Comic p.12). Doctor Kruger says: "Indeed, I was sealed inside, too. Until today. You have my eternal thanks for freeing me of my prison."
- Previews World Ghostbusters: Answer The Call #1 7/9/17Synopsis reads: "On a routine house call to dispose of a simple Class III spook, Abby, Patty, Erin, and Holtzmann encounter a truly terrifying Class VII that appears to be feeding on fear."
- Jillian Holtzmann (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #3" (2017) (Comic p.3). Jillian Holtzmann says: "We don't know why Kruger left, where it went, what it's planning, we know nothing."
- Abby Yates (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #3" (2017) (Comic p.3). Abby Yates says: "Kruger doesn't even see us as a threat."
- Patty Tolan (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #3" (2017) (Comic p.9). Patty Tolan says: "All we know is where Kruger was... oh, no."
- Abby Yates (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #3" (2017) (Comic p.13). Abby Yates says: "These things seem... bound here, like we suspected Kruger was."
- Erin Gilbert (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #3" (2017) (Comic p.13). Erin Gilbert says: "Okay, so, let's just spread out and try not to distrub anything... for some records or files that might give us some insight into what Kruger was doing down here."
- Patty Tolan (2017). IDW Comics- "Ghostbusters: Answer The Call Issue #3" (2017) (Comic p.20). Patty Tolan says: "...Because I just figured out what Schreckgespenst is up to."