Add a flying snake. It’s a mob that hides in the leaves of trees in the jungle. It is green so you would have to look pretty closely through the leaves to find it. When you aren’t looking, it leaps from its tree and uses its “wings”(really just flaps of skin on the sides of its body) to glide down and bite you. If you are bitten, you will be poisoned. The snake can’t bite through iron, gold, diamond, or turtle armor. But It can sometimes get through leather, so be sure to bring protective clothing! Also, a snakebite will greatly reduce your armor’s durability. This comment was inspired by the paradise flying snake, which really does glide down from trees to catch its prey.