Scratch

I need to know how to make enemies in a scrolling game who appear only when the main sprite is near them  and move back and forth on a certain platform, kind of like the enemies in archknights game.

Ok how I did it was fairly simple.

First create a variable for the sprite called movement.

Set this variable to how far to the right you want the sprite to be.
Try setting it to 1000 and it should appear around the third platform.

Then make a script like this.
In this example I used the variable "platforms" as the scrolling variable.

<when green flag clicked>
<forever>
<set x to( (( <{ platforms }> <+>  <{ movement }> ))


I didn't include a script to hide the sprite but you should be able to do that on your own.

That is the way I programmed the enemies in archknight's adventure