EnderDragon doesn't have a health bar after you respawn it.
What I expected to happen was...:
I expected the Dragon to spawn and look like the old Dragon and have all the same attributes as the original with a health bar showing the top of the screen as usual for every boss.
What actually happened was...:
The Dragon spawned and I was surprised because the health bar didn't show up and so I couldn't tell how much health it had while I was fighting it. I started to think that it couldn't be killed so I tested it by using a sword that one shots the EnderDragon (when it can be killed of course) and the Dragon died.
Steps to Reproduce:
1. Make a Creeper face out of clay on the endstone to respawn the EnderDragon
2. You're Done
3. YOUR'E DONE!
Dupe of MC-83239