HEAT oven to 375ºF.
MIX meat, stuffing mix, water, eggs and 1/4 cup pasta sauce. Shape into 16 (2-inch) meatballs. Insert 1 cheese piece into top of each meatball, with end of cheese piece just showing at top. Place on baking sheet. Top each with olive slice to resemble eyeball.
BAKE 20 to 25 min. or until meatballs are done (160ºF). Meanwhile, cook spaghetti and heat remaining pasta sauce as directed on package and jar.
DRAIN spaghetti. Serve topped with meatballs and sauce.