Paint one half of the first paper plate blue.
Paint the entire paper towel tube blue. Set aside to dry.
Cut the second paper plate in half. Paint the outer edge of one half with blue, leaving the center white.
Once dry, glue the painted half plate (with the white center) over the unpainted half of the whole plate
Cut a wide, grinning mouth shape out of red construction paper.
Glue the red mouth over the white area of the half plate.
Use a white marker to draw sharp teeth on the red mouth.
Cut one pointed fin (for the top) and two curved fins (for the sides) from blue paper or another plate.
Glue the pointed fin to the back/top edge of the full plate (above the shark’s head).
Glue the two curved fins to the underside of the plate near the mouth.
Glue the painted paper towel tube horizontally across the middle back of the full plate—this will act as the shark's hammerhead.
Finish by gluing large googly eyes or paper eyes to both ends of the paper tube