Expose the owner of the produced offspring

[clemens-tolboom]

https://docs.godotengine.org/en/stable/getting_started/scripting/gdscript/gdscript_exports.html#examples

# Another node in the scene can be exported as a NodePath.
export(NodePath) var node_path
# Do take note that the node itself isn't being exported -
# there is one more step to call the true node:
var node = get_node(node_path)