Zack Effron playing a young Mathew Perry (when Perry is turned 17... again).
Psyche has done it twice, the young actors don't really look much
like the older characters.
This guy here:
was played by this guy (the older version) in Sandlot:
Joseph Gordon Levitt playing a young Bruce Willis in Looper. With CG effects, and possibly prosthetics.
Another example of casting two actors who don't necessarily look alike.
Its the same when casting fathers, mothers, sons, daughters, brothers,
and sisters. They cast characters for their acting, the actors sometimes
don't look related.
There are rare cases where an actor's son could pass as a younger
him/her:
But usually they have to cast an actor who looks just enough like the other
older actor to pull it off, but also must be a good actor. I think they
usually cast for their acting ability and the looks second, but I could be
wrong about that.
and like i always say, I am not saying I have my heart set on Wilson as young
Hank Pym. Just that I'd be fine with it. Also I would like to see the psychological
stuff of Pym in the movies. And that might be why some people want this.
They feel like casting Douglas will lead to the movies skipping over the cool
character stuff and history of Pym. Like how he decided to experiment with ants
and shrinking after his first wife was killed. Or how his changing hero persona is
a sign of mental instability. Or how Ultron is evil and stuff because he used his
own brain patterns.