Opponent has robot token with a +1/+1 counter and Starport Security out. I have Codecracker Hound. I play Specimen Freighter and target both opponent's creatures. The +1/+1 counter on the robot token is removed but still shows as 3/3 and both targets remain on the field. For the rest of the game, these two targets stayed put but weren't valid targets, and the robot token never untapped.

I assume my opponent could see the ghost creatures since the hover visual showed up. Unsure if this affected their gameplay since they didn't block for the rest of the game.