In "The Pornscape", The Ponytail Killer eyeballed Jessi through the bushes and considered killing her and taking her ponytail before she let down her hair, making her an undesirable target. Just then, Karl Lagerfeld happened to walk by, shifting the killer's attention toward himself, as the killer desired to steal the celebrity's iconic ponytail.
Later in the episode, Karl Lagerfeld's pet cat, Choupette was seen pawing at a dumpster outside of Temple Beth Amphetamine. Jay opened the dumpster for her to let her into the dump only to find the murdered body of Karl Lagerfeld, lying down in there, with his ponytail cut off. Jessi and Jay reported this to the police and they looked deeper into the case.
- In the lore of Big Mouth, Karl was murdered by The Ponytail Killer in 2017. Coincidentally, the real-life Karl would die a mere two years later, on February 19, 2019.