If you noticed a rise in manic behavior on the 16th Street Mall in the past year, the fault might lie with It'Sugar at the Denver Pavilions, Colorado's first link in a gargantuan national chain of candy stores that claim to do everything sweet and bad for you, bigger and badder than anyplace else. The proof is in the packaging: At It'Sugar, you can walk out of the store with a five-pound keg of gummy bears or the "world's largest box" of any of several popular candies, from SweeTarts to Nerds, or a one-pound Snickers bar. Sweet!