I am trying to think of this animated movie that I watched as a kid. I'm just guessing that it was made in the 70's or 80's. I can remember only bits & pieces of it, but hopefully someone can help...
A cave, maybe it's up high... on the side of a mountain, perhaps?
The 2 characters I can (*barely*) remember are young boys. One of them has a horn on his head (like a unicorn) and I remember him as a loud & angry little guy; he talks about his dad too.
The other boy I remember even less of; he may have been human, I can't remember. But I don't think that he was loud & angry.
I also think it could be a japanese-type animated cartoon.

I know it's a long shot to think that anyone could "Name That Movie!" with only these tiny fragments as clues, but it doesn't hurt to try!

Maybe a little devil (Beezle)and
A young unicorn (Unico)?

Fantastic Adventures of Unico

view scene
Unico meets Beezle

Maybe it was the film Magic Boy?? Its he only jap movie I know that was made I think in 60-70's

I have no idea how you managed to do that, but THANK YOU SOOOO MUCH!! I'm going to start looking for it right now, I can't wait to watch it again!