"I didn’t realize then that I would never see Ozzy again after that night," Butler writes of the July 5 "Back to the Beginning" show in England.

Tony Iommi, Black Sabbath guitarist and co-founder, told UK broadcaster ITV that Osbourne was “frustrated” during the band’s farewell concert on July 5. The heavy metal icon died less than three weeks later, on July 22, at age 76.

Given that major rock and metal acts such as Mastodon, Metallica, Halestorm, Lamb of God, Gojira and Alice in Chains were involved in the concert, you’d think that Megadeth would’ve been as well. According to LoMenzo, though, they missed the moment simply because they weren’t invited.