It’s easy to understand why so much of what’s been written about Spain’s Mourn has focused on the band’s youth. Having recorded its self-titled debut in just two days, the group of teenagers grabbed attention because the result was far better than it had any right to be. A year later, Mourn has shown that its debut wasn’t a fluke, as its follow-up for Captured Tracks, Ha, Ha, He. shows a more refined side of the band. The A.V. Club is premiering “Second Sage” below; the song sees the band adding darker, moodier elements to its garage-rock compositions, resulting in a sideways take on classic post-punk. Like the other songs from Ha, Ha, He. that have been released, “Second Sage” shows that Mourn is growing in subtle ways, somehow skipping that awkward, gangly phase entirely. Guitarist-vocalist Jazz Rodríguez Bueno says: