way too many creepers

I was playing minecraft for a while with no problems and then tons of creepers spawned in the same place. When I went near them they scattered everywhere. I logged out to see if that would fix it and when I logged back into my world a lot of them were gone but there were still quite a few. I tried to take a screenshot at the start when there were many of them but the minecraft screenshot button didnt work for some reason so this is a pic of those who are left by using an external screen capture software.