The Polar Bear Add-on for Minecraft

Imagine you're walking through the woods and the further you go, the more strange noises you hear? You speed up, but it seems like it's following you. You don't know what it is, but you want to run away without looking back. You start running and when you think you've escaped, you run right into him. He's the polar bear. He has the same speed as you, but he's infinitely superior in strength, agility, and endurance.

 He will watch you and then kill you...

 He can squeeze through narrow spaces to reach you, he crouches and crawls to kill you, and he can break any block to reach you.

(Credits to dolphinmaster for his code for the crawl and crouch, very talented!!)