Dreamsicle Jell-O

1 large box orange Jell-O
1 small can mandarin oranges, drained
1 pound tapioca (already made)
1 (8 ounce) container Cool Whip

Make Jell-O according to box directions. Place in refrigerator until partially jelled. Remove and add remaining ingredients. Mix. Return to refrigerator for at least another hour.