Chocolate Castle by Lexaloffle Games Ltd.

Solving a level in Chocolate Castle usually produces brightly colored balloons drifting up from the bottom of the screen, signifying your success. However, on Set 2, Room 5 and Set 3, Room 26, there is a green snake that must be maneuvered through a field of white rabbits. If you solve the puzzle by allowing the snake to eat any of the rabbits, you will get black balloons at the end, signifying a rabbit's demise. Solving these puzzles without eating any of the rabbits produces the usual colored balloons.