A simple I made to allow you to ruin everything, somewhat inspired by other mods that do this, but mine is made by me, so it is weird :D
features: "The Source" (TS) block that is crafted with 4 rotten flesh (F) 4 fermented spider eyes (E) and a nether star (N) arranged like so:
[F][E][F]
[E][N][E]
[F][E][F]
Upon right clicking it, it will turn all nearby blocks into "hungering flesh" (hf) blocks that spread, if you break TS it will turn nearby hf blocks into "starved hungering flesh" (shf) a sub type of hf blocks that turns other hf blocks into shf blocks and decays if there are no hf blocks near it.
both hf and TS are easily broken with an axe, and hf is highly flammable
IF you have suggestions put them in the comments and if added your username will be in the changelog :D
updates will be added when I have enough Ideas for things,
currently planned features(if it has a question mark it might be added): new flesh variants, hostile flesh mobs, flesh residue?, spreadable_blocks tag that contains any blocks that can spread and starve
if you want an older version, ask and ye shall receive.
update 2:
features: nutrient extractor or something, used to get rid of flesh that has been starved
flesh variant 1: unstable flesh, explosive
flesh variant 2: satiated flesh, does not spread, sometimes spawns things, (may be buggy atm)
flesh variant 3: diseased flesh, randomly poisons things
and misc bug fixes/optimizations
1.0.0: added "the source", "hungering flesh", crafting recipes, and basic "spreading" and "decaying" mechanic
2.0.0 added many new flesh types, updated spreading/decay mechanics, bugfixes and a nutrient extractor (may be a lil buggy)