When she was alive, Gertrude was the eldest daughter to Sir Aldridge. On October 25, 1894, Sir Aldridge woke up and found no breakfast. He was angry at his servants, but when he found each and everyone of them, they had been murdered. Gertrude had murdered them all. To spare the family public humiliation, they locked her in the basement and feed her through a the door slot. Years later, the mansion was sold and her spirit resided in the basement.
After the mansion's tour guide had an encounter with Gertrude, Ed Mulgrave Jr., the mansion's historian, asked Erin Gilbert for help. Erin, Abby, and Holtzmann arrived to research the events that had recently happened. Ultimately, Erin made direct contact with Gertrude and introduced herself. After a moment of trying to communicate with her, Gertrude projected Ectoplasmic vomit on Erin and then flew through the wall and out into the streets.
- Gertrude was created from the idea of a character like Lizzie Borden. 
- Gertrude was originally going to be an ugly old woman. 
- Bess Rous wore a LED light suit and was placed in a rig that took her up and down. 
- For one take, Rous unexpectedly screamed and scared Kristen Wiig and all the others. 
- ↑ EMPIRE Online "Empire Podcast: Ghostbusters Spoiler Special with Paul Feig" 14:34-15:07 7/27/16 Paul Feig says: "No, it was... we just liked the idea of this sort of spooky history of this Lizzie Borden-type character who killed people and the family locked her down. That's a real -- Katie Dippold likes that sort of spooky stuff like that and it just felt... I -- we really like the idea that there's the ghost that would be powerful enough to work their way back or would stick around to be re-energized are the one's carrying enormous hatred and evil with them."
- ↑ EMPIRE Online "Empire Podcast: Ghostbusters Spoiler Special with Paul Feig" 15:09-15:37 7/27/16 Paul Feig says: "Originally it was written to be this sort of ugly old woman then I worked with Bess Rous. She was one of the stars of my show "Other Space" I did for Yahoo! that's been geo blocked here which I'm trying to desperately get you guys because I love it and she's so great. She's perfect. She can do that almost Kubrick-ian thing where 'beautiful face but minute she tips her head down like the face becomes evil and the eyes get evil' and stuff like that. So I was, it has to be Bess."
- ↑ The Verge "Analyzing the Ghostbusters trailer with director Paul Feig and writer Katie Dippold" 3/3/16 Line reads: "To be able to get Bess Rous, who was one of my actors in Other Space, I thought that would be great if she was the ghost [in the museum scene]. So we got here in this LED light suit, and put her on this rig that took her up and down."
- ↑ The Verge "Analyzing the Ghostbusters trailer with director Paul Feig and writer Katie Dippold" 3/3/16 Line reads: "But then she could interact with my cast, and even surprise them. At one point, she did this thing where they didn't expect it: she just screamed. It scared the shit out of Kristen and all the others. It was great."