First phase: The infected would start to smile more often, or feel joyful without a reason, normally telling others to smile without a reason as well.

Second phase: The infected would have yellow patches forming on their face, almost like a mask, due to smiling, their face would start to stretch ove time, and it is painful.

Third phase: The patches would start to get harder as it forms a smiling mask over the infected's face, scientists say they heard muffled screams before it fully hardened.