The Black Simmer

I’m not sure how to add pictures to this forum so I’ll try my best to explain the situation. So while I’m in CAS, randomly the thumbnails for some CCs will have a horse (or maybe llama) icon. If I click on any CC thereafter, my sims entire body from head to toe will be a mixture of purple, red, blue and grey. And my game will crash 3 seconds later. This has been going on for a while now. I’m not sure what causes it and this happens in all my save files even when I start a new game. Is anyone else having this issue? Please help me.