SCP Foundation

You could make the object itself weirder; maybe it replaces hearts with random objects instead of dry ice, and they still work but are incredibly painful. Or use it to go into a deeper exploration of your theme - how does it really judge good people from bad? Lots of people behave ethically in society while suffering from existential nihilism and lack of empathy as symptoms of mental health problems; how does the book react to them? This seems like a tough approach to pull off successfully with this particular concept because the idea of a force that judges your morals and does something to your heart if you fail goes all the way back to ancient Egypt. you'd have to really dig to come up with some original way to present it.

The other approach is to craft a good plot around your object; SCP-4950, posted just today, is a perfect example of of a very simple object (demonic summoning circle) that's been shown a lot of ways in a lot of media, but it's got an extremely well written discovery log that makes it feel fresh. You could show a plot happening around your object - maybe the dry ice hearts are painful but never stop working like a real one does, so a shaman or someone is using it to give sick people "transplants," but the recipient has to do a bunch of evil stuff for the ice heart to take. something like that would allow you to explore some less obvious angles to the nature of the anomaly and give the audience a series of events to react to.

Note that doing both is the best option! For example, 4950 has some twists on the nature of a summoning circle and how it works, which spice up the article, but the narrative is really what makes it work. If that article were just a description of the circle itself as it sits in Foundation containment, it wouldn't be so good. I think the concept you're describing here would need to be handled the same way.