Spray eight 12-in. x 10-in. pieces of foil with cooking spray. Place one ear of corn on each piece of foil; spritz corn evenly with butter-flavored spray. Fold foil over corn and seal tightly.
Grill, covered, over medium indirect heat or bake at 400° for 25-30 minutes or until corn is tender. Combine the butter, horseradish, mustard, garlic, salt and pepper; brush over corn. Sprinkle with paprika.