Formulas Fatal to the Flesh is the fifth full-length studio album by death metal band Morbid Angel. The title of this album is a biblical reference: it contains the letter "F" - the 6th letter of the alphabet - capitalized three times, which refers to the Number of the Beast, 666. The Satanic themed lyrics of previous albums had been replaced with lyrics about the Ancient Ones, which would become the primary source of Morbid Angel's lyrical content from this point on. This is the first album to introduce singer/bassist Steve Tucker, replacing David Vincent, and has some lyrical content written in Sumerian.