like, for example, The Jar's spawned red hearts should have some sort of thing tagging them as having spawned from using The Jar, so if a mod adds something that randomly replaces red hearts, they could make their replacement code ignore those red hearts
like, for example, The Jar's spawned red hearts should have some sort of thing tagging them as having spawned from using The Jar, so if a mod adds something that randomly replaces red hearts, they could make their replacement code ignore those red hearts