Someone in Hollywood with a sense of humor is poking fun at power agency CAA. A series of ads and posters with the agency’s iconic logo instead spelling “CAAN’T” have popped at Century City Mall. The prank was inspired by a Page Six blind item last month, asking which Oscar-nominated director groused at a high-level meeting about being so frustrated with his Hollywood agency that he yelled, “They should be called Caan’t! Caan’t, Caan’t, Caanttttttt!” Reports said CAA demanded that the posters two blocks from its headquarters be removed. A Hollywood insider told Page Six of whoever commissioned the gags: “Those signs are right around the corner from CAA, and they aren’t cheap. For a month, they must cost around $100,000. Whoever did this has to be somebody with serious balls and serious coin.” A source tells us rival agency WME — which poached CAA clients including Carey Mulligan and Brett Ratner in recent weeks — was behind the ads, saying, “People need to get a sense of humor in this town.”