Casting to actor using actor reference failed?

Okay, well see. I understood that… somewhat.

However I still don’t really undestand it. The reason is 2 fold.

I saw a video that I can’t really find that quicky anymore, where a guy made the comparison that casting to a blueprint, is like asking for Star Wars Episode 3.

But not specifying which Star Wars Episode 3 you’re asking for. I.E. is it the movie, the game, the lego set etc.

And the way he said to solve this is by simply making a variable that is a reference to an actor, to plug into the cast node. So the cast knows which parent class to look for. As shown here:

Second. If that’s not how it works. Then what is a reference? And how can you reference something in a blueprint that isn’t actually in that blueprint. But is another blueprint somewhere in the level?