This is a little mod I made for myself back in 1.2.5(there is no 1.2.5 release, dont ask), and I quickly rewrote it for 1.4.2 as I think others would appreciate it too. It was originally thrown together as a fancy debugging tool, but it gives the game a bit of a… rpg feel, so I thought I would release it.
When anything living takes damage, the damage they took will bounce off their head, with a cool little effect.

Now shows the Mob portrait preview with current health when you mouse over mobs! Every registered Mob type(mod mobs too) can have this preview adjusted using config files, so full compatibility is easy.
Have a mob displaying incorrectly? Press period and click the Advanced button and descriptions for the adjustments are listed.