The YouTube star released a full 15-minute video on Wednesday revealing that Eilish had unfollowed her on Instagram, and lamenting what she feels is a truly depressing tragedy.
Mongeau -- who is a self-professed obsessive for the "Bury a Friend" singer and even dressed like her for an entire week as part of a YouTube video earlier this year -- decided to record a lengthy, Eilish-inspired sadness montage, that half seems to shade the singer as much as it mocks Mongeau's obsession.
Mostly shot in black and white, the tribute video shows Mongeau drinking wine while crying, eating a pie while laying on the floor, sobbing on a roof top and drinking wine in a bathtub, all while wearing different looks of Eilish's signature style of full-length hoodies and sweatshirts.
Mongeau starts the video with a dramatic reenactment of her discovering she's been unfollowed, and then her breaking the news to her manager, Jordan Worona.
"Yo Jordan. This is absolutely the most detrimental thing I’ve ever filmed myself telling you in the entire history of us working together. And that sounded sarcastic but I actually mean it," Mongeau can be heard saying as she films her manager.
"I’m actually sad! I found this out yesterday and went through hard shock and now I’m sad as I make this video but I have to make a video," she added, explaining that the only silver lining to this disaster is it provides her with more content for her channel. "I have to get views out of it because nothing else good could happen from this."
Cue the super bummer music and then stylish, surprisingly funny sadness montage.
Even Mongeau seems to understand why this happened. Despite the sadness, she admits on the video page, "Honestly I deserved it."
Just to back things up for context, Mongeau has actually met Eilish in the past, when she went to one of the artist's concerts last year. This pic she posted to Instagram -- which shows her bowing down and attempting to hug what appears to be an uncomfortable Eilish -- actually speaks volumes when it comes to this latest news.