For a bat doughnut: cut a caramel wafer cookie in half. Dip one pointed end of a wafer cookie in the melted chocolate and place behind the doughnut on the left side; repeat with the second half of the cookie and place behind the doughnut on the right side to form "bat wings."
Brush a dot of chocolate onto the back of 2 candy eyes and place on the doughnut above the bat wings. With a paring knife, create 2 slits on the inside of the doughnut hole, right below the eyeballs. Dip the flat ends of 2 candy corns in chocolate and press them into the slits to create fangs. Repeat with 3 more doughnuts. Allow the doughnuts to stand until the candy is well-set, about 15 minutes, or refrigerate to speed the setting process.
For a cat doughnut: cut 3 slits in a doughnut with a paring knife--2 on the top-outer-edge of the doughnut (for the ears) and 1 on the inside of the hole towards the bottom (for a tooth). Dip the flat ends of 3 candy corn pieces in the melted chocolate. Press 2 into the upper slits to form ears. Press 1 into the bottom slit to create a tooth. Brush a dot of chocolate onto the back of 2 candy eyes and place on the doughnut just below the ears. Brush a dot of chocolate onto 1 confetti sprinkle and glue it in the center beneath the eyes to create a nose. Use the jumbo sprinkles to form 3 whiskers on each side of the nose; adhere with chocolate. Repeat with the remaining doughnuts. Arrange the decorated doughnuts together on a large tray and serve.