Megadeth bassist David Ellefson spoke in an interview with Thunder Underground and revealed the first song Dave wrote on the bus coming home from Metallica. He said:

“I think it’s more something we looked back on later. Because when you’re doing the record – I mean, even ‘Dystopia.’ As we were doing it Dave [Mustaine] even looked at me and said, ‘If they don’t like this I’m out of ideas.’ [Laughs]

Some of these songs were like putting together math projects, different combinations of notes that gcan bind the riffs, and it was fun! It was very clever as far as like doing textures, like different blocks falling into place. So it was really a fun process to do. But I think that’s it, you kind of leave it all in the studio, you leave it all on the studio floor. You just throw everything you’ve got right there at it. And actually that’s what ‘Peace Sells’ was, that’s what ‘Rust in Peace’ was. Especially ‘Rust in Peace’ was like that.

‘Peace Sells’ is interesting because a lot of the songs on ‘Peace Sells’ were… I mean, ‘Killing is my Business’ and ‘Peace Sels,’ those all songs were kind of written in the same couple of years – from ’83 till ’84. So it’s interesting that some of the tunes like ‘Devil’s Island,’ ‘The Conjuring,’ those were very, very early Megadeth songs.

Especially ‘Devil’s Island’ – and that didn’t end up making it until album two in 1986, three years after the band had been formed. In fact, ‘Set the World Afire’ on ‘So Far, So Good… So What!’ – that was a very first song Dave wrote on the bus coming home from Metallica. [Laughs]

So it’s funny, three albums later it finally gets recorded. Some of these ideas that float around… You know, they just take what they take. Album is really a collection of ideas whose time has finally come.”

Click here to entire interview.