Add CGI droids to Wrath of Kahn?
Add a terrible CGI jazz number to the opening of Final Frontier instead of Row Row Row Your Boat?
A scene where Kirk walks around one of the whales from Voyage Home and steps over their tail?
What would you add? Take a film and go to town.
One tribble is added to every single scene aboard the Enterprise. They do nothing. They are simply there. Occasionally one rolls across the background during a tense dialogue exchange.
And add a little Tribble sound that only shows up on surround sound setups, always behind the viewer