How to make the boss's health go down

Help Requests
#1

I need to be able to shoot my bow at the boss, and it will take away it’s health. No idea how though.

#2

Game: http://flowlab.io/game/view/112068

#3

.

#4

Okay, now I understand. thanks!

#5

Hey john, if you look at my game, when you get to the boss stage it doesn’t show the health bar. Am I doing something wrong?

#6

.

#7

mmmm k ill try that

#8

Is there any way that I can make the bar appear only when I’m in the boss room?

#9

.