Exporting glorious tweerock from St. Louis, bUNNYgRUNT is the gifted trio of Karen Reid (drums), Matt Harnish (guitar) and Jen Wolfe (bass) (with Pulsars founder Dave Trumfio as “unofficial fourth member”). Sandwiching the eight catchy songs on Action Pants! between two coolly casual singers — the wispy Reid and the boyish Harnish — the group underpins its brisk jangle-pop with occasional blasts of afterburner racket power. Those lulled into a false sense of cuddlecore giddiness by the folky rush of “Superstar 666,” “Transportation Pants” and the organ-flecked “Just Like Suppertime,” and not sufficiently alerted by the sterner presence of the autobiographical “I Am Curious Partridge,” may be knocked for a loop by the clattering intensity of “G.I.2K” and “Tadpole.” Musically adorable and not at all coy, bUNNYgRUNT cuts a colorful swath of freewheeling style through what is often a refuge for the plain and unassertive, giving Action Pants! the sharp creases that stand out from the crowd.