San Antonio’s live music options this week include plenty of performers willing to take chances, from the dark alt-country sounds of Rattlesnake Milk to the unapologetically extreme metal act Mutilation Barbecue. Folks even have the option of shaking it to a pair of trailblazing DJs:  Kaskade is known for bringing progressive house music to a wider audience, while Disko Cowboy has the audacity to blend country twang with electronic dance music. Let’s take a look.