The smiling critters are going through a infection that causes the infected critters to go insane and attack everyone, the infected can still talk, but use it to try to convince you there not infected, the infected have sharp claws to spread the infected.
The signs of infection are listed below
1. Constant stuttering and changes in actions
2, nose bleeds often without any damage to the nose
3. Enjoys the feeling of being alone and claws growing
4, red eyes,sharp claws, fully infected, violent