How do i remove rings when player uses custom ability?

[Powershows]

Hey guys! creator of Blue Streak here and I'm a bit confused! I would like to remove 20 rings when the player presses custom 2 for their ability.
I've searched the wiki and I don't know what fits for this case. the file is down below if you need it. if you don't want to edit the file then just tell me what I can do about this.

 

[Zipper]

You need to set player.rings, player.health doesn't exist, and player.mo.health is unused. Well, it's not used for rings at least. (I swear I've said this somewhere else before)

Also, just write "20", "$20" means "the 20th variable at the left of the expression". Lua isn't very Assembly-pilled.