Shortly before midnight Thursday, Atlanta trap provocateurs Future and Young Thug, coated the world with the surprise release of their collaborative mixtape, Super Slimey.

As the aptly-titled mixtape suggests, the slime is super thick on this one. It flows from their cups in the form of the codeine syrup both artists frequently hail as their vice of choice. It coats their voices, presumably altered by said syrup, into a gritty granular texture in Future's case ("Group Home"), and transformed by the dependable Auto-Tune technology that takes Young Thug's already animated squall into cyborg-like territory ("Mink Flow"). And it's steeped in the content, which, if you know anything about the mind-numbing debauchery that inspires the city's trap sound, is always mired in the mud.

The new release, which quickly charted in the top 10 of iTunes overall albums chart upon release, features standout production from the likes of Southside, Richie Souf, Wheezy, London on Da Track, Mike WiLL Made-IT and more.

But in a genre where emcees often shine the biggest lyrical spotlight on their most-valuable producers, Future reserves his biggest shout-out on Super Slimey for his recently deceased studio engineer, Seth Firkins.

"Go check my profile, I beat the verdict (I beat the verdict!) / I was kicking it in overdrive, for Seth Firkins (Yeah, yuh!)," Future raps on his solo song, "4 Da Gang."

It's a rare acknowledgement that speaks volumes of someone whose job description often revolves around being as invisible and indispensable as possible to the major recording artists for whom they work during long, odd studio hours. Though often overlooked, engineers are increasingly becoming celebrated contributors to the trap sound due to the significant role they play in recording signature vocals.

Firkins, who was 36 when he passed away in Atlanta last month, began his career about a decade ago as a studio engineer recording in the city's music scene for then-emerging artists Future, Rocko and, eventually, others such as Zoey Dollaz and Young Thug.

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