You can’t put Slough Feg’s Mike Scalzi in a tidy box. As front man of the cult local metal band — its most recent album, 2010’s The Animal Spirits, earned critical raves — he prowls the stage with a vaudevillian flair while performing blistering, melodious tunes (sample titles: “Trick the Vicar,” “Ask the Casket”. Plus: he’s a sci-fi fan; he teaches philosophy at Diablo Valley College; and he occasionally pens highly articulate, commenter-rattling columns for respected metal blog Invisible Oranges. Slough Feg will play a rare show Aug. 17 at the Elbo Room, opening for New Wave of British heavy metal legends Diamond Head. Voices will soar; faces will melt.