Metallica's promotional blitz in support of their new Hardwired ... to Self-Destruct LP arrived at The Tonight Show Starring Jimmy Fallon last night, and per tradition, the group sat in with Fallon and his house band, the Roots, to perform one of their signature songs on toy classroom instruments.

It added up to an utterly unique rendition of "Enter Sandman" that saw frontman James Hetfield blowing into a toy clarinet and guitarist Kirk Hammett playing a melodica while bassist Robert Trujillo and drummer Lars Ulrich used miniature versions of their usual instruments — all stuffed into a small space, making a racket with the rest of the large ensemble.

As Tonight Show fans are well aware, this is far from the first time Fallon has had a musical guest give a hit the toy instrument treatment. Previous visitors include Adele, who performed her hit "Hello"; Carly Rae Jepsen, who delivered her signature single "Call Me Maybe"; and the cast of Sesame Street, who naturally tackled the show's theme song — none of whom rocked the classroom as hard as Metallica.

The band's Tonight Show visit came in the middle of an 18-hour stretch in which they barraged fans with videos filmed for each and every Hardwired track. As previously reported, they'd already released clips for “Hardwired,” “Moth Into Flame” and “Atlas, Rise!,” and starting at noon yesterday, they posted a new video every two hours through 6AM ET the following day.

Hardwired ... to Self Destruct arrives in stores tomorrow. Check out 10 things you need to know about the new album to get you ready for its arrival.

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