I want a MineCraft (version 1.8) mod that creates the following "mob" (enemy creature).
- can slowly mine through certain blocks (such as sand, gravel, clay and dirt) in order to get to player
- begins spawning (rare) after 7 days have passed in game-time
- begins spawning (uncommon) after 14 days have passed in game-time
- begins spawning (common) after 21 days have passed in game-time