[8][non-primary source needed] Also in 2019, Sematary formed the underground hip hop collective and record label Haunted Mound, becoming the group's frontman.

[13] Upon its release, Paste praised it as "easily the hardest-hitting rap record of the year right now", while Revolver's Eli Enis called it "beautifully belligerent".

[18] That same month, "Fuck the World", a collaborative single between him, Chief Keef, and fellow Haunted Mound member Hackle, was released.

[20] Steckler was inspired by witch house band Salem and rappers Chief Keef, Black Kray, and Yung Lean to start rapping, with the latter motivating him to pursue a career in music after he saw him perform at the Warlord American tour.

[14] Paper's Ivan Guzman called his and Haunted Mound's lyrics "slasher film-esque" and their production style "blaring" and "blown-out".

[5] His sound was called "distinctly post-internet" and a "[fusion] of psychedelic SoundCloud-era rap à la Bladee and Yung Lean with menacing horrorcore drums and spooky witch house synths" by Eli Enis of Revolver.

[5] Sematary helps design Haunted Mound's merchandise—which, as of 2024[update], make up most of the collective's revenue—and its mascot, a screaming tree named Harold.