Mob Rules is Black Sabbath's tenth studio album, released in 1981 following the success of Heaven and Hell. It peaked at number 29 on the charts. It was the first album to feature Vinny Appice on drums, who had replaced original member Bill Ward on the tour in support of the previous year's Heaven and Hell. This led to Ozzy Osbourne dubbing the line-up "Geezer and the three Wops". It is rumoured that the cover art for this album, by famed artist Greg Hildebrandt, contains a heavily-disguised message that reads "KILL OZZY,". It is apparently located toward the bottom of the picture, on the ground, written in a dark, crimson colour. However, the message is barely legible, and it is widely believed that the purported text is coincidental. The artwork was not created specifically for the album, for one thing, having been done in the 1970s, but was licensed for use. The lyrical themes are dark, notably on tracks such as "The Sign of the Southern Cross" and "Falling Off the Edge of the World". The Live Evil album was recorded on the Mob Rules tour. The album is included in the Black Sabbath box set The Rules of Hell. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.