The robber dubbed the “This Ain’t No Joke Bandit” abandoned all levity and pleaded guilty Sept. 3 to 18 counts of robbery and attempted robbery that included hold-ups at a yogurt shop and TGI Friday’s restaurant in La Jolla. Without a plea agreement with prosecutors, Jamel Tishan Powers, 24, of El Cajon, faces 20 years and eight months in prison, according to what San Diego Superior Court Judge Jeff Fraser told him would be the maximum sentence. Fraser also said he would consider a lesser sentence that would range from 13 to 18 years. Sentencing was set for Oct. 16. Powers remains in the South Bay Detention Facility on $350,000 bail. Powers earned the nickname because he repeatedly said these words: “This ain’t no joke. I’m serious — this is a robbery.” The loss to businesses in the spree is well in the thousands of dollars, but Deputy District Attorney Makenzie Harvey said she had not figured the exact loss from all victims. The series started March 29 with a hold-up at a McDonald’s restaurant, and then Powers picked yogurt and ice cream shops. On April 5, Powers robbed two employees at the TF Yogurt shop at 8800 Villa La Jolla Drive. Powers had robbed three other people at other yogurt shops elsewhere that day, according to court records. Powers also attempted to rob the TGI Fridays in La Jolla on April 28, but got away without any money. He expanded his robbery menu to include hamburger joints, a cafe, pizza places, a Marie Callender’s restaurant and a sushi shop. Powers left his fingerprints on a counter at an ice cream store, and he was arrested May 12 by San Diego police. Powers never displayed a weapon, but victims testified at a July 23 preliminary hearing they feared he had a gun.