question:  Whah dzy of the week did Shark Tank debut on?
sentence: Shark Tank (based on the Dragon's Den reality format) also became a midseason sleeper hit on Sundays in the spring of 2010; the following season, it became the tentpole of the network's Friday night schedule, gradually helping make ABC a strong competitor (after being paired with 20/20 and beginning with the 2012–13 season, the Tim Allen sitcom Last Man Standing) against CBS' long-dominant drama/reality lineup on that night for the first time since the "TGIF" lineup ended in 2000.