[TOMT][Movie][1990s] Possibly Australian scifi movie with a Predator ripoff looking for a tentacleheaded alien kid

Help me TOMT, you're my only hope.

I'm looking for a 90s probably australian scifi movie, targeted to kids or young adults. An alien kid crash lands on Earth and is being hunted by another vaguely Predator alien who can cloak and fire vague bullshit energy blasts.

A human kid finds him and adventure ensues with the totally-not-predator being electrocuted in some pond or something else shallow and watery.

I seem to remember the alien kid having tentacle hair kinda like Diva Plavalaguna from Fifth Element and also maybe being blue or gray. Also hard weird fingers but I can't remember enough details.

There was also some grandma who could transform into a blindingly bright bullshit (alien) rainbow warrior but I think I may have mixed that with some other movie or show.

Please help me, this has been randomly popping into my brain and driving me nuts for around 15 years.