Busta Rhymes paid tribute to his late friend and collaborator MF DOOM as "a God MC and incredible human being".
The rap legend - whose real name was Daniel Dumile - passed away on October 31, according to a statement by his wife Jasmine on December 31.
DOOM, aka Zev Love X, Metalface and King Geedorah, worked with Busta frequently since their 1991 track "Nitty Gritty Remix" with the former's group KMD.
Busta admitted he is struggling to come to terms with the devastating loss of the beloved rapper - who was just 49.
Alongside a video of their 2016 track "In The Streets" - which also featured The Chicago Kid - Busta began his lengthy post on Instagram: "Rest easy on levels that words can't describe @MFDOOM."
"It has taken me days to come terms with this enough to type about it and I still can't believe it or come to terms with it. I'm completely f**ked up by the loss of this God MC & incredible human being!! Over 30 years of friendship & brotherhood almighty!! I wanted to believe this was another elaborate scheme by the great Whodini MF DOOM himself but this time I have received the confirmations that it wasn't."
On DOOM's legacy, Busta added: "This has meant something to our culture that no other MC has because he figured out something that none of us before him and that was to be completely free!!!"
DOOM suffered a devastating loss when his beloved 14-year-old son died of unknown causes. The rapper announced his son's death on Dec. 18, 2017.
"KING MALACHI EZEKIEL DUMILE 2/22/03 – 12/18/17 The greatest son one could ask for. Safe journey and may all our ancestors greet you with open arms. One of our greatest inspirations. ‘Thank you for allowing us to be your parents. Love you, Mali."
Doom also lost his brother Dingilizwe Dumile, aka KMD's DJ Subroc, who was killed as he crossed a busy highway in New York in 1993.
KMD was dropped from the record label the same week Subroc died.
KMD was best known for their bubblegum rap song "Peachfuzz," featuring 3rd Bass and Grand Puba on the xylophone.