This is a zombie class I created some time ago, but basically it's a class that regenerates its HP or in other words heal. It regenerates X (this is a cvar that can be changed) HP every X seconds. The regeneration stops when the zombie gets shot, but it resumes again when no one shoots at it. Moreover, after X times of HP recovery a cooldown activates for X seconds. After the cooldown it starts to regenerate its HP again.
There are some extra "things" to the plugin .... like showing how much HP you have recovered and a sprite every time you recover HP .... as well as 2 sounds .... 1 when you recover HP and 1 when the HP is fully recovered
Here are a few screenshots so you can see what it basically is: