This is the old Tank from gamemode_Zombie (Also known as Left 4 Block) by Rotondo turned into a bot hole and also a playertype. 1500 HP, takes no knockback, and a lack of a standard player animations. As you'd expect it does quite a bit of damage in comparison with the default zombie and even has a slightly larger range. The damage can of course be modified with the default bot events, as well as the health. He makes no death or pain sounds, and emits no pain emitters, as he doesn't have time to react to pain.
Also so you can event your own with Onbotdamaged and onbotdeath.
Speaking of...
A nice little bonus. These are sounds from Gamemode_Zombie, and feature the Tank's bellowing and grunting, the witches's crying and anger at being disturbed, and the sounds that were not directly ported from L4D, which were made with a acoustic guitar and a keyboard, presumably played by Rotondo? Hm. Anyway, these had some real problems with their noise levels. I have attempted to turn down the noise on these sounds, so they sound slightly better.
L4BGameOver.Wav
L4BHordeIncoming1.wav
L4BHordeIncoming2.wav
L4BHordeIncoming3.wav
L4BHordeIncoming4.wav
TankZombieDeath.wav
TankZombieIdle_1.wav
TankZombieIdle_2.wav
TankZombieIdle_3.wav
TankZombieIdle_4.wav
TankZombiePunch.wav
TankZombieYell.wav
WitchZombieAttack_1.wav
WitchZombieAttack_2.wav
WitchZombieCry_1.wav
WitchZombieCry_2.wav
WitchZombieCry_3.wav
WitchZombieCry_4.wav
WitchZombieDeath.wav
Enjoy!!