THIS MOD IS INTENDED FOR SINGLEPLAYER USE, ALTHOUGH IT IS POSSIBLE TO PLAY IN MULTIPLAYER, YOU MAY ENCOUNTER BUGS.
Things to note
This mod is heavily based off of Pehkui, to the point where it can be considered a mod of a mod. Make sure to check out the original mod here. There is also no starting command, just put it onto your game and mobs will start growing.
How it works
Mobs start off extremely tiny, but eventually get so large they start suffocating themselves in walls. Most, if not all entities are affected by this, including but not limited to: Items, boats and arrows. Damage of entities is not scaled, however, creeper explosions do vary depending on scale. Dont worry though, the scale of the mobs reset back to small whenever you exit the world, making sure that your world is still playable in the case of a mob growth emergency.