Creeper

You will be walking alone in the night, perhaps exploring a forest, and you will hear a slight "hisss" before an explosion, and then everything will go black. The Creeper is an abomination of nature, a walking plant-like creature with four legs, an armless torso and head, evolved for stealth, with a deadly final attack. The Creeper stalks the land at both day and night, searching for humanoids and animals to kill. A creeper's only attack is to stealthily sneak up to a person and then suicidally explode in a kamikaze. When a creeper explodes, it spreads its tiny seeds in all directions, which latch on to a surviving person, who will then unknowingly spread them. If a person dies from the blast, the seeds will feed on the nutrients of the corpse. Creeper seeds grow into new mobile baby creepers after only a few weeks. Creepers have a mixture of sulphur, saltpetre and charcoal which naturally occurs in their body to form a type of gunpowder which they use for explosion. Creepers have also evolved eyes, which appear as fist-sized black orbs on its face, which give it darkvision. To stay alive, once a week a creeper must drink freshwater and eat a handful of soil using its primitive mouth hole, and absorb sunlight on its chlorophyll skin. Creepers live for about a year before shrivelling and dying if they have not released their seeds in an explosion. The creeper's urge to stalk prey and explode next to it, releasing its seeds, is an overpowering instinct that it is born with. If you kill a creeper in melee combat before it explodes, your sword might be covered in its green blood and some of its seeds.