Slowly We Rot is the only album on which Obituary used E standard guitar tuning - all of the band's other albums use D standard tuning. Despite this, it is widely considered as Obituary's heaviest album.
One scene in the movie Joe's Apartment has Jerry O'Connell wearing an Obituary shirt with the Cause of Death album cover on it.
The song "Internal Bleeding" from Slowly We Rot features growling all throughout the song - but no official lyrics. All "phonemes" are, in fact, made up.
Slowly We Rot was dedicated to a friend of the band who died before the recording of the album.
During Obituary's inactive period between 1997 and 2003, Donald Tardy played in Andrew W.K.'s touring band, going as far as to wear an Obituary shirt during W.K.'s appearance on Saturday Night Live.
Given that John Tardy's vocal style is more or less the trademark of Obituary's sound it may suprise you to find out that he was in fact the vocalist by default as he was Don Tardy's brother and used to help them out by singing while they jammed. For obvious reasons he has remained their vocalist throughout their entire career.
After the release of Slowly We Rot original bassist Daniel Tucker apparently disappeared without a trace, leaving the band no choice but to replace him with Frank Watkins. Frank stayed with the band for around 20 years, until deciding in 2010 to focus on playing in Gorgoroth. Obituary later welcomed another veteran of the scene as their new bassist: Terry Butler (ex-Death, ex-Six Feet Under, ex-Massacre).
Obituary have never officially printed their lyrics and vocalist John Tardy is known to "make up his own words" on occasion to get the desired sound.
The new Obituary logo (as can be seen on The End Complete) has been considered Roadrunner's best selling shirt print in its history.
Obituary's The End Complete is crowned the best selling pure death metal album ever released, selling over 100,000 copies in the US, and over a quarter million worldwide.