How would I go about making a dark souls type health tween

i want to make a sort of chaser bar underneath the health bar to recreate this

the yellow is what i mean.

are you trying to tween the object below the health bar?
if so then you can use GuiObject:TweenSize() it is easy to tween frames now. though what do you mean by “the yellow”

i think op is talking about the gradient (green->yellow) being added when the bar size gets decreased

you could recreate this with UIGradient at an offset

Easiest way is to just have 2 healthbars, 1 red (on top) and a yellow below. Whenever change set the red, delay ~1s and then tween the yellow.

yes I am, i dont know what your talkng about htough