Green as plains grass, and standing slightly over a block and a slab tall, the Creeper is a very terrifying mob to encounter in the wilds.

Long have players feared the destructive power of these monsters, and yet there has been little written of them, aside from cautions to avoid or quickly kill them at all costs, I hope to remedy this lack of documentation.

I have procured a number of Test Subjects from the tower and my findings are as follows:

Creepers exhibit animal-like properties, however they are not in fact animals. Using a piston forced glass containment device, I have been able to study their biology up close without fear of explosion.

By taking samples of the specimin, our science labs have determined that the Creeper is actually an incredibly reactive mycological entity. Creepers actually share more in common with red mushrooms, on a biological level, than they do with players.

The Creeper begins its lifecycle as a spore, which germinate in dark areas untill they are able to attain locomotion. At this stage the Creeper follows visual and auditory cues to find a player, and once does so enters its reproduction cycle.

The speed and voracity of this reaction is incredible, in a matter of ticks the Creeper's body engourges with spores and explodes violently. Victims that are not killed outright spread the spores and propegate the species, victims that are killed become hosts for new Creeper offspring.

...

In writing this, I've also had to revise our mob handling procedures and anti-contamination practices, the results are chilling and have engendered a new respect for what I once thought were simply suicidal monsters.

Some further notes:

Creepers can be misled into initiating a mating cycle on unliving mobs, and though they don't prefer these as hosts, will germinate in zombie or skeleton corpses.

Dogs and wolves will instinctively avoid Creepers and do not see them as food, domesticated dogs will not eat food that has greater than one part per million of Creeper in it.

Cats do not pay any special attention to Creepers, but the Creeper reproductive drive is completely suppressed in their presence.

Creeper reproductive cycles can be interrupted by removing their target from line of sight, or by blinding them totally. An uninteruptable reproductive cycle can be initiated by specifically lighting the primary nerve cluster on fire, this is not reversable.

Creeper remains (when killed before they are able to propagate) can be dried and refined into gunpowder, and the concussive blast of a creeper is enough to damage the reinforcement of surrounding blocks.

Creepers, for unknown reasons, seem to collect and incorpirate music records internally whenever possible, and they can often be found inside undetonated remains. Care must be taken to harvest a collected disk.

Creepers are dangerous and single-minded in their desire to propegate, knowing what I now know, a death from Creeper explosion is not something I would wish on anyone.

Cat domestication programmes have been initiated, to issue every citizen a companion cat.

Comments:

What's the deal with them certain to have a disc inside them if they are killed by a skeleton arrow? - Ukulelelesheep

A developed Creeper either collects or generates one internally like a pearl, the recorded sound is either a collection of sounds it has heard or something else is developing them. All Creepers seem to have them, but most causes of death seem to destroy them, specific reagents in Skeleton arrows seem to prevent this.

Unfortunately because the reagents in Skeleton arrows make them more brittle than normal, once activated they can not be physically collected.