Café Lulu’s Halloween party promises not only the usual parade of costumes, but music from two easygoing Milwaukee bands. Uncle Larry, who play quirky alterna-pop with ample nods to Talking Heads, They Might Be Giants and Pavement, should let their already zany sense of humor run wild for the holiday. Openers Big Fun 4 Ever, meanwhile, craft sweet, synthesized dance tunes about youthful romance and rebellion. And, for good measure, the night also promises something called The Live Undead Mermaids Horror Playwe don’t know what that is, but we’re assuming it’s awesome.