It’s that spooky season again. Where to live it up on or around the Day of the Dead? It’s not just about candy anymore — although it is still about blood, bones and Batman masks. Fear the food trucks. Friday, October 26 is the last time Off the Grid will appear at Fort Mason Center until next March. They’re turning their farewell gig into a Halloween haunt with decorations, live music from Rolling Stones cover band Black Angel, a costume contest (extra points for Stones-related guises) and Halloween specials at 34 food vendors and two full bars. (Hint: beef-heart tacos and pumpkin-cuchinta ice cream.) Off the Grid is also celebrating…