The movie I’m looking for is an Australian Kids Movie about a monster living in a lake or pond. The monster is called the Donggagin  or Donkagin or something like that and it emits bubbles periodically. Ends up being a digger left in there and with pressure it releases air bubbles. This movie has stayed in my mind for years and I would like to show it to my children now. Hoping someone knows this movie and can tell me the name. Thankyou.