{Scab-Clan Giant} enters the battlefield, only creature my opponent has, has hexproof. What happens?
its the same as if he had no creatures on the field. theres no legal target so the ability cant resolve.
Follow-up question: opponent has 3 creatures, 1 with hex proof. Is the hexproof creature included in the randomization of creatures?
since the giant uses the word "target" and a hexproof creature isnt a valid choice, it wont be included in the random selection.