There are a few ways you can reference a variable from another script:
Find the proper path of the node which has the script with the variable in question. Your path is probably wrong, maybe you attached the script to a node further down the tree or something.
If you need to get the value of such a variable, you could also instance a new script and get it from there. You could do something like this:
var example = preload("res://Scripts/<script with variable in question>.gd")
func _ready():
scale = Vector2(0.25,0.25)
example = example.new()
print(example.<variable in question>)
Note that this method will not change the original value, it will just grab the variable you want and make a copy of it (that’s why you use the new() method)
Based on your screenshot of the scene tree, I can see where you’re confused.
Calling get_node("World/NPCs/NPC") on your Player script would look for a child of “Player” called “World”, which is exactly why you’re getting a null instance result.
“World” is the scene root, so you need get_node("/root/World") to access it.