During Anvil’s October 27 show in Stockholm, Sweden, the band were joined onstage by guitarist Mats “Mappe” Björkman (Candlemass) and singer Messiah Marcolin (ex-Candlemass) for a performance of “Metal On Metal.” You can see fan-filmed footage of that below. Marcolin told Blabbermouth the following: “It’s the first time in 16 years me and my old…