Fake Spawning in spawner

I found a spider spawner in an amplified world. After torching the spawner to keep spiders from spawning, i saw that skeletons started spawning. However, these where glitched skeletons. They didnt move, didnt look at me, and they defied gravity. But, they continued spawning around the spawner until there were over 100 of them in the spawner room, and the lag was unbearable. You can hit the skeletons, but only once. When you hit one of them once, that skeleton is now even more glitched, and cant be interacted with in any way shape or form.