Final answer:
Gargoyles were the decorative waterspouts of the Middle Ages used to prevent rainwater from running down masonry walls, and they also served as symbols of evil and religious adherence.
Step-by-step explanation:
The decorative waterspouts of the Middle Ages designed to prevent rainwater from running down masonry walls are called gargoyles.
These were first designed in the 13th century and used extensively across the roofline of Gothic cathedrals.
Gargoyles were not only functional but also served as symbols of evil and were meant to threaten people and encourage religious adherence.