I also had a thought about the impact in might have on objects. It might be a bit complex but maybe it could apply an effect to the objects themselves once they enter the event horizon of the portal. Maybe it stops them for a split second then zips it right in. Maybe it makes them start fading to a different color or leaves a trail of the object itself. Maybe it ejects some particles right where an object entered. It could potentially affect the scale of the object as well. Just some food for thought :)