This heart should always be placed at the rightmost slot, always granting your next rightmost heart a 10 hp cushion before it starts taking damage. It can be used effectively with Adrenaline, as there is no risk of losing the heart after taking its hp below 50%. There is basically no situation where you ever need to swap out this heart, as long as you put it on the rightmost slot your run should be a lot easier.
- Undying Heart is the only heart that cannot be destroyed in the entire run
- Losing this heart still plays the heart loss animation
- There was a bug in earlier demos which granted invincibility when undying heart was used with body bag hearts
- This is technically the weakest heart in terms of HP in the game