Stun is a level 80 Magic spell. When cast on an opponent, their attack level is reduced by 10%. The spell can only be cast if his stats haven't already been lowered, meaning you can not stack stat reduction with multiple spells in a row.
Stunning is commonly used as a method for Magic training.
The popular locations that are used for training with Stun are Edgeville, casting at skeletons in the first few levels of the Wilderness; at the caged Monk of Zamorak at Varrock Palace and in the Magic Guild basement, where there are caged zombies. However, any location with a safe spot can be used.
Because Stun cannot be autocast, repeatedly casting it on monsters involves a lot of clicking.
When using this method, the maximum experience rate is 108,000 experience per hour, at 1,200 casts per hour (1 cast every 3 seconds).