kevinkool is a well-known admin on the Hypixel server (mc.hypixel.net) so I took it upon myself to recreate some of his known characteristics into Minecraft, and this is the result of that work.
Firstly, this mod requires Forge (the latest forge for the specified Minecraft version).
Please search Google for how to install mods on 1.6.2
Let's start off with some images:
As you can see, kevinkool is an aggressive mob and WILL attack you. He takes on the same characteristics as a zombie, except, he is hard to catch, they will often start speeding around the map at break-neck speeds, making it nearly impossible to kill them.
A max of 5 can spawn in one biome, with a minimum of 3, bear in mind they are EXTREMELY hard to find, so it is recommended you cheat and pull in a spawn egg for him (I will make a way for you to create him in the future)
He drops diamond pickaxes when killed: