When Boba Fett mugs the camera in the SE Jabba the Hutt scene in ANH, add a line, “You’re next, hehehe.”
Literally came to this thread to post this exact thing right now.
So instead, off the cuff: On Endor at the Ewok celebration, as Luke starts to turn away from the ghosts Anakin changes from Shaw to Hayden. Luke turns back, to make sure he wasn’t seeing things, and Anakin changes back. This repeats a few times before Luke catches him in his Hayden form and the flash each other a playful smile.