The maker of Red Bull energy drinks is challenging a Virginia craft brewery’s use of the word “ox” in its brand name. Red Bull filed an opposition with the Patent and Trademark Office late last month against trademark registration applications from Old Ox Brewery in Ashburn, Va., arguing that an ox and a bull are “virtually indistinguishable to most consumers.” In response, the brewery compared Red Bull’s action to that of a “corporate wedgie.” Chris Burns, president of Old Ox Brewery, wrote on the brewery’s website on Sunday, “You are a big Red Bully.” A phone message left for a Red Bull spokeswoman seeking comment was not immediately returned.