I want to create a mob that destroys blocks it walks through.  I'm kind of new to this so could some one help?

Well, when your mob is moving, just take the blocks ahead and set to air blocks and generate any particle effect you might want to show.

 

The one other tip is that you'll probably have to code up the AI for the movement yourself because the built-in AI uses pathfinding that will avoid blocks .

Well, when your mob is moving, just take the blocks ahead and set to air blocks and generate any particle effect you might want to show.

 

The one other tip is that you'll probably have to code up the AI for the movement yourself because the built-in AI uses pathfinding that will avoid blocks .

 

Sorry, again, kind of new to this how can I do this?

So you know how to place a block in the world? To "destroy" a block in Minecraft it actually gets replaced with a Blocks.air block.

 

Do you know how to make a custom entity? Then in the entity's update method you can create the movement and also destroy blocks as you wish.  Every entity has a posX, posY, posZ position that you can convert to a block position so you can then find the blocks you need to destroy.

 

Why don't you start by making an entity that just stands there, then work on the movement and block breaking.  I have a tutorial on custom entities here: http://jabelarminecraft.blogspot.com/p/creating-custom-entities.html