Lag Time?

This has only happened on League for me but for the past few games. Sometimes I get strange lag where my ping and connection are fine but when I cast spells and see enemies cast spells it will pause the animations of every thing for a few seconds. A few seconds later all of the animations and cooldowns appear to have gone through and done what they are supposed to do, but I cant see where anyone moves or what they do in response during the lag time. It makes the game incredibly difficult to play.