what spell was lucius going to use on harry

In the movie adaptation of Harry Potter and the Chamber of Secrets, Lucius Malfoy pulls out his wand and begins to incant a spell "Avada..." before being stopped by Dobby. Avada Kedavra is known as the killing curse, and using it supposedly results in immediate transfer to Azkaban for a life sentence. However, it is unclear whether Lucius intended to kill Harry or Dobby. According to a fan theory, Lucius may have intended to kill Dobby to tear away his newfound freedom as well as revenge/punishment to make Harry feel guilty for being the one responsible for Dobbys death.