I know there's a few zombie plugins out there, but none of them really interest me because I am looking for one that can increase the speed of them so they're more dangerous and players can't out run them. If anyone could help me out I would greatly appreciate it.

Surprised you want to speed them up they're pretty fast to begin with

You can just out run them. Eventually they get caught on something and you're free. I wanted a server with zombies like the people with rabies on World War Z

Every entity has a velocity, you can try to increase it

How exactly do I do that? I don't know anything about that stuff lol

I can code something like 'Fast Zombies Horde',
message me if interested :p