Fade Out

modulate is a Color with four parts: red, green, blue and alpha (a). Alpha is how solid the node looks. 1 is solid and 0 is invisible.

To tween one part of a property, write the part after a colon:

var tween = create_tween()
tween.tween_property(self, "modulate:a", 0.0, 1.0)

"modulate:a" is a single number, so the end value is 0.0. Red, green and blue stay the same. This also works for "position:x" and "scale:y".

A fade is not the same as visible = false. The node stays visible but becomes fully see-through.