Wayne Krantz has made a concept album, though not in the sense of a tightly-wound narrative spooled around an extended song-cycle. No, the eight tracks that make up Good Piranha/Bad Piranha are really four tracks that are, in fact, eight. That is the concept. For the mostly instrumental set, Krantz took a foursome of songs and played them each twice, using a different drummer and bassist for the first four than for the second, with vocalist Gabriela Anders reprising her cameo role on both halves. Perhaps this explanation is far more confusing than it needs to be, but on another note, and maybe more importantly, is there such a thing as a good piranha? In Krantz’s estimation there is, and both good and bad chomp through interpretations of such diverse artists as Radiohead’s Thom Yorke, on “Black Swan,” and MC Hammer, for “U Can’t Touch This,” with slicing, rawboned runs that start in terrestrial melodic territory and land somewhere west of Mars. Only the lifted line from the original Rick James “Super Freak,” and Anders’ otherworldly voice appear with any conspicuous repetition, more as signposts on the circuitous journey than redundancy. Too much is going on within the stellar interplay between Krantz and his crew for it to matter anyway. In his terse liner notes Krantz writes this is him cutting loose, and that he still likes playing guitar. That’s good news from a good piranha, and especially good from a bad one.