Crimson Head

Crimson Head/Breaker Zombie
They appear when someone dies from infection(he/she turns into one). They are one of most dangerous enemies, even more dangerous than Stalkers. They are fast, tough and deal a lot of damage. If you're about to die from infection better suicide to avoid causing trouble for teammates. At first they walk slowly, but when they notice you they start running after you. They are extremely dangerous in Free Roam mode.