"Booyakasha" is a catchphrase that is common among the Ninja Turtles, but mostly used by Michelangelo, in the 2012 TV series. It replaced the classic "Cowabunga", first used in the 1987 TV series. It is pronounced /buːˌjɑː.kɑːˈʃɑː/ (boo-YAH-kah-SHAH). Metalhead - First time being used by Donatello …