What I expected to happen was...:
Describe what you thought should happen here
In 1.8.8 I have an ender dragon to display a timer via its HP bar which works in the overworld
What actually happened was...:
When I loaded the world in the snapshot the HP bar was missing from my screen. it did not re-appear when I summoned a new one ether

Steps to Reproduce:
1. Summon the enderdragon in the over world(1.8.8)
2. upgrade to 15w32c
3. summon a new dragon just to be sure.