Whisk soy sauce, oyster sauce, hoisin sauce, red wine vinegar, garlic powder, sriracha hot sauce, and ground black pepper together in a bowl until sauce is smooth.
Preheat an outdoor grill for high heat, and lightly oil the grate.
Place corn on the grill and brush with the sauce; cook for 5 minutes. Turn corn and brush the other side with sauce and cook until tender, about 5 minutes more.