The Zombie Hiker

The Zombie Hiker is a mob that spawns in extreme hill biomes.  It holds a climbing pick axe and can use it to climb.  It can jump from a wall onto you. 

When you kill the Zombie Hiker,  it will drop its climbing pick axe.  You can use the climbing pick axe to climb the side of steep hills and mountains.   But if you try climbing in the rain, you slip.

You can enchant the climbing pick axe with a new enchantment called, climb speed.  Climb Speed makes you climb faster.    There is only one level of climb speed. 

If you kill a Zombie Hiker it may also drop frozen rotten flesh.

If you eat frozen rotten flesh it gives you hunger and freezes you.

You can put the frozen rotten flesh in a brewing stand with an awkward potion to make freezing potions, which you can turn into splash freezing potions or lingering freezing potions.