Hide Eye Candy Menu Option (Source)
Recently we added an option to the Game tab in the menu called "Hide Eye Candy". Some of our more competitive players requested the the option to hide some of the less subtle movement on Summoner's Rift. We added the option to disable things like butterflies, dragonflies and the water wakes to help competitive players focus on what they care about, the gameplay.
The next PBE deploy should have the hook ups enabled. Let us know if we missed anything that should've been added and if you have any other feedback regarding this new option.
Edit: Only ambient critters that persist after 1:55 will be disabled by this option. You can continue to perfect the dark ritual necessary to spawn the Duck.
League of Legends : New 'Hide Eye Candy' option