Like most sparklers, these are extinguished after a short while -- with several large bites. To make two dozen, place 4 ounces chopped semisweet chocolate in a heatproof bowl set over a pan of simmering water. Stir occasionally until melted; remove from heat. Using a pastry brush, coat the upper third of each pretzel rod in chocolate. Cover with sprinkles; stand pretzels upright in a glass. Place in the refrigerator until firm, about 5 minutes.