Minecraft Blockmoeba - Living Block Creatures

Blockmoeba is a Minecraft Fabric mod written in Kotlin that turns ordinary blocks into giant living creatures. A Blockmoeba can be a colorful glass blob, a nearly invisible piece of the landscape, or even a creature built from any Minecraft block you choose. It breathes, reshapes itself, follows players, hunts them, and can grow to thousands of blocks.

The source code is available on GitHub.

Playing Blockmoeba with My Kids

The best test was turning the Blockmoebas loose while playing Minecraft with my kids. The video starts at 26:55, when I explain the mod and begin spawning them.

One of my favorite moments was a small, hostile Blockmoeba stalking Chloe. Its nearly clear body hid in the dark while its magma core glowed inside. She did not realize it was following her until it was already attacking. :)

A small sneaky Blockmoeba with a magma core stalking Chloe.

How It Moves

A Blockmoeba is not a normal Minecraft mob with a model. The creature is a changing set of real blocks in the world. To move, it retracts blocks from the edge farthest from its target and grows new blocks along the leading edge. The result is a rolling, fluid motion while the creature remains one connected blob.

The movement system adds a little randomness for a more organic shape, discourages thin tentacles, and gives gravity a slight influence. A separate breathing cycle grows and retracts a few blocks, making the whole creature pulse even while it moves. When a Blockmoeba passes through replaceable plants or snow, it remembers and restores those blocks behind itself.

Players can fight one by mining its body. Every broken block reduces its size, and destroying the final block kills it.

Personalities and Bodies

Blockmoebas can be configured with several different behaviors:

• Loyal Blockmoebas follow the nearest player and move toward their feet.
• Hostile Blockmoebas accelerate as they get closer and try to engulf the player at eye level.
• Sneaky Blockmoebas freeze whenever a player is looking toward them, then move again when nobody is watching.
• Camo Blockmoebas sample nearby terrain and build their bodies from the surrounding blocks.
• Lava stomachs keep a moving magma core inside a translucent body.
• Custom bodies can be made from any registered Minecraft block, from amethyst and sculk to TNT.

The standard colors use stained glass with a solid core: pink, blue, green, purple, orange, cyan, red, and yellow. Their transparency makes it especially fun to watch a magma stomach shift around inside as the outer body flows across the terrain.

Commands

Spawn a Blockmoeba where you are looking. Every argument after type is optional:

/blockmoeba spawn [type] [max_size] [loyal] [speed] [sneaky] [aggro_range] [lava_stomach]

For example, this creates a small hostile pink Blockmoeba that only moves when it is not being watched and has a magma core:

/blockmoeba spawn pink 80 false 12 true 80 true

The type can also be camo or a block ID such as amethyst_block, sculk, obsidian, or tnt.

Blockmoebas can also race. The mod builds gold starting markers and diamond finish markers, then releases up to eight colored creatures:

/blockmoeba race [racers] [distance] [max_size]

Useful cleanup and debugging commands:

/blockmoeba status
/blockmoeba clear [radius]

Development Logs

These three short dev logs follow the Blockmoeba as its movement and behavior evolved.

Dev Log

Blockmoeba currently targets Minecraft 26.2 and is built with Fabric, Fabric API, and Fabric Language Kotlin. The source lives in the mods/blockmeoba directory of the Minecraft repository.