Cut out small eye and mouth shapes from 12 slices of bread. Spread butter on one side of each bread slice.
Heat a nonstick pan over medium heat. Place one uncut slice, butter side down, in pan. Top with 2 slices cheese. Place one slice with cutouts, butter side down, in pan. Cook until bread is golden brown and cheese melts. Assemble sandwich; keep warm. Repeat with remaining bread and cheese to make 12 sandwiches.