This track is believed to have been written by Tim Staffell. The track is very, very heavy, with powerful drums and guitar, and good vocals from Freddie; it sounds like a live recording, but it definitely is not. There is debate about when the track originates from, as some people believe it was recorded for the 'Queen' or 'Queen II' albums between 1972 and 1974, and some people believe it was recorded for the 'News Of The World' album in 1977, due to Freddie's vocal performance and the use of rototoms on the track. Some sources also suggest that the track features Barry Mitchell on bass, instead of John, but apparently this rumour was started by somebody trying to sell an acetate CD of the track.
There are a number of versions of this track available, I have heard four recordings which are the same track but in varying quality, ranging from very good to very poor. The song lasts for typically 3:00, but some MP3's include upto 8 seconds of dialogue at the start. Some tracks also appear to be slightly faster than others, reducing the time to 2:54, but otherwise they are the same.
In addition to the standard versions, there is also a 2:38 edited version; this is identical to normal but at the end, an echo/phasing effect is applied to the drum/guitar, to give it a very sudden and definite ending.