[1.7.10] Special mob powers

[Aerden]

I'm making a mod that adds a mob that has five heads. I want the mob to be immortal unil the main head is destroyed, I also want that the player must destroy the four other heads before, being able to destroy he main head. Can someone help me try and make this?

[Aerden]

Forgot about this post, and yes I mastered java a long time ago. Thank you for helping this solved my problem