This is the Rotten plant when it is growing. This plant requires darkness and stone.
And this when it is done.
If you destroy the plant when it is done it will drop rotten flesh. It will also drop rotten seeds which can be used to grow these plants.
Rotten flesh isn’t very useful in Minecraft so I have added this.
This is cooked flesh and it can be eaten without poison. It also gives you more food.