The music of Mark Kozelek, whether made with his former band Red House Painters, under his own name, or as Sun Kil Moon, has been described many ways: dreamy, melancholic, and wistful come to mind. With the release of his newest covers album, Like Rats, you can add creepy to the list. The songs he’s picked to cover have lyrics that are alternately menacing and depressing, either overtly or because they’ve been stripped of their accompanying upbeat music. Kozelek has never shied away from darker themes in his music: the yearning loss in RHP’s “Michael,” death and loneliness (and maybe serial killers?) in SKM’s “Glenn Tipton,” regret and self-pity in his cover of John Denver’s “I’m Sorry.” Kozelek’s voice often soars over the intricate guitars, though, and its sweetness lends the songs a faint glimmer of hope. But on “Like Rats,” he sings a register lower than usual (more on that decision later) and piles dark song upon dark song until the listener is off-balance from the assault of negativity. The album is barely 30 minutes in length, and anything more might be too much.