I didn't have much time to make this, but I don't think many people would like to fight this creep in MC. I'm just making this up as I go xD. I don't think this boss is from any video game, I just made it up. With a little help (The eyes and the luring part) from my weird brother :).

How he came to be:
Nobody is sure how this monster came to be. Whether he dropped from the sky or evolved from another mob, but rumor has it that he was born from a long abondoned dungeon. That dungeon had been inhabited at one point by an NPC. This NPC was a plant breeder, finding new species of plants every day. (Yes, this NPC was the NPC that brought all the new beautiful flowers to MInecraft, you know, from tht cool update they had ^.^).  Then, nobody is really sure about this part, but people think that, after that NPC had died, its body morphed with some flowers, and got possessed by some creepy mob. Nothing weird about that :D

What is it:
This skin is a creepy flower boss. His smile and spooky eyes will frighten anyone. Oh, and don't forget the creepy laugh! He lurks in sunflower patches at night. He might lure you into the flower patch with sparkly mist or something. Then he attacks, with viciuos teeth and retractable thorns, sometimes poisining you. Also, don't try and fight him in the rain, because he grows larger the longer he fights in rain or water. He can also grow roots from his feet, sometimes used to strangle you, or to use as an anchor against knockback swords or bows.

How it relates:
This skin relates to the theme "Boss Battle" because I would think that in Minecraft, this Creepy Flower Boss wouldn't be a regular mob. He would be a rare find, with alot of stregth and health.

Hope you like it :). I tried to make it creepy-ish.
This is my first contest, so I really didn't know what to do!
I apologize for not being able to use a 1.8 skin format. :((