Hello, everyone! This theory was made by reddit user HoveringPigs1. It gives a good idea of how life in the Nether began and how they survived and became successful in such a hostile environment. It's a really good theory and I hope you all enjoy!

The Nether is filled with strange and fascinating life. Most of them seem to be familiar to us for some reason, but a few are completely alien and unique. It is still a mystery how life in the Nether came to be, and how they managed to become successful in such hostile environment. But today, we'll try to solve this mystery by analyzing what we know about the life in the Nether, and by trying to find out what the clues and information we have tells us about the Origins of Life in the Nether.

Let's start by looking at the currently known lifeforms living in the Nether. Many of them seem to resemble Overworld Mobs in many ways. Magma Cubes are comparable to Slimes, Piglins and Hoglins resemble Pigs, and the Smaller form of Nether Fungi Trees are very similar to Overworld Mushrooms, both of which belong to the same group which is Fungi. This might suggest that many of the organisms in the Nether originated from the Overworld, possibly through Naturally-Occuring Portals. It only takes Natural Materials commonly found in caves and volcanic zones of the Overworld (obsidian) arranged in specific formation (which can be done through a long time of weathering or constant contact of water and lava), and a spark of fire, for these Portals to form. Another evidence for how this (transportation of Overworld Mobs to the Nether through Naturally-Occuring Portals) could be possible is the Overworld Mushrooms that grow surprisingly quite commonly in the ground of the Nether. Though there are a few Nether Mobs which don't resemble any Overworld Mobs and look very alien, these are Ghasts and Striders, so probably not all of the Nether Mobs are of Overworld Origin.

But how did they survive and become successful in such hostile environment?

Let's take into account some factors which are exclusive to the Minecraft Universe, and would affect life in many ways: .

1. It appears that heat transfer by conduction and radiation between living entities and nonliving-solid objects don't work in the Minecraft Universe. A proof for this is the fact that you can stand on a block located next to a lava pool or a heat source without getting your feet burned, even without boots! This isn't exclusive to the player, nonfire-resistant mobs also don't take damage when standing on a block next to a lava pool. Also, your hands don't get burned and you don't get damaged whenever you're holding a solid item that's supposed to be hot, like a bucket of lava. Doing these activities in real life would burn your feet or hands without any protective equipment. But hey, you still get damaged by magma blocks and magma blocks are fully solid objects right? Yes you get damaged by magma blocks. However, if you look closely at magma blocks, you'll notice that there are animated and bright linings in its texture which appears to be liquid lava or semi liquid lava. Heat Transfer by conduction or radiation between Living Entities and Liquid does work in the Minecraft Universe. Therefore, because of the liquid or semi liquid lava linings on magma blocks, it would still hurt you when you stand on them. How about Snow Golems and Striders? Snow Golem's hot biome damage is based on the ingame code biome temperature rather than the solid ground temperature. Biome Temperature must be based on air temperature rather than ground temperature, because Deserts and Nether Biomes have the same Ingame Code Biome Temperature, yet the Nether Biomes have solid ground which are hot enough to evaporate water while water doesn't evaporate on Deserts. Heat transfer through radiation between living entities and gaseous medium does work in the Minecraft Universe, so Snow Golems would still get damaged, not by the ground temperature, but by the air temperature. Striders get cold on land because of the absence of a heat source coming from hot liquid lava. Striders are usually more affected by temperature of surrounding liquids, rather than the air temperature. This is because they don't take damage on biomes with low biome temperature, they don't take damage on snow, but they only take damage on water in its liquid state. Neither do they heat up standing on fire or soul blue fire, but only heat up when standing on liquid lava. .

2. It appears that the biological rule for the requirement of water for Organisms on land is less strict in the Minecraft Universe, and that land organisms seem to be more well adapted to dry land in the Minecraft OverWorld than in the real life Earth. The higher percentage of land covering the Minecraft OverWorld (higher than real life Earth's) would motivate such adaptation among organisms that took on land in the Overworld. .

3. Looking at Factor#1 in which heat transfer between Entities and Solid Nonliving Objects don't work in the Minecraft Universe, this would result in the Organism's Bodies being cooler than the hot ground temperature of the Nether which is hot enough to evaporate water. Since the solid ground and ceiling of the Nether is hot, Water would only exist in its gaseous form in the Nether. Water must be abundant in the Nether in the form of Steam or Fog. There also appears to be thick fog covering most biomes in the Nether, atleast thicker than that of the Overworld's. The surrounding materials would alter the colour of the fog, example of this would be the soul material turning the fog's colour bluish in the SoulSand Valley. Because the organisms are cooler than the ground, this would then cause the steam water in the air of the Nether, to condense around the organisms in little droplets that cannot be seen ingame because of the pixel size vision restriction. This would allow lifeforms to obtain liquified water and survive in the Nether. This would create humid and moist conditions which would be ideal for the growth of Fungi, which already grows in the Nether in large numbers and enormous sizes, which are in turn, eaten by many different fungivore organisms, which are then eaten by carnivorous organisms, whose dead bodies are consumed by Fungi, and thus, forming a functioning Ecosystem and Cycle in the Nether. .

But why would they go to the Nether in the first place? It's possible that they got there by natural events, curiosity, got trapped, or were carried by a larger organism. Probably many of the organisms in the past that got through these Portals failed to survive and died. It's highly possible that the first Overworld colonizer organisms that managed to lived and become successful in the Nether, are the Early Fungi. Since many previous organisms that got through the Portals failed to survive and died, the dead bodies of these unsuccessful organisms provided food (if not the bodies of the Nether Organisms which are completely alien and native to the Nether) for the first successful colonizers which is the Early Fungi, which also happen to be decomposers. They also probably live alongside a few smaller and successful decomposers, like bacteria and microbugs, but these smaller organisms are too small to see with the naked eye, especially in Minecraft where there's pixel size vision restriction. After a while, larger and mobile animal organisms which got through the Portals, and managed to survive on diet of Fungi alone, also become successful. The first known mobile animal organisms of Overworld Origin, whose descendants are still alive today, are probably Slimes-Magma Cubes (Mojang have that Magma Cubes forage upon Mushrooms that grow in Basalt Deltas). The moist conditions of the Nether are ideal for such slimy and watery organisms. But they can encounter another problem, Fire and Lava.

It appears that Magma Cubes have managed to solve this problem, they've managed to develop a layer that could protect them from extreme and direct heat. How did they do this? Let's look at the items that they drop, which are Magma Creams. Magma creams are used for fire-resistant potions. Magma creams, for some strange reason, are crafted by combining Normal Slime balls and Blaze Powder. Blaze Powder can be crafted through Blaze Rods, which are dropped by Blazes. Since Blazes are found only inside structures, have a strange body structure of a lump of rock with face and hot rods circling around it, and emit strange sounds which you'd hear in some machinery, Blazes might be constructs or artificial mobs rather than natural and real living organisms. The materials used to create Blazes, Blaze rods and Blaze powders, are probably the same materials that the Early Slimes used to develop a Fire Resistant coating by combining their skin layer made out of slime balls, and these blaze materials. Perhaps these materials were once found naturally in the wild, but are now only found within Blazes. Perhaps these materials are actually some kind of ore, or organs of a fire-resistant organism that is completely native to the Nether and are not of Overworld Origin. Also another possibility is that Blazes aren't constructs, but simply rather a mob that's completely native to the Nether and are not of Overworld Origin, which the Nether Fortress civilization managed to domesticate and train to protect their structures. Since lamarckian inheritance works in the Minecraft Universe (evidence: dye two sheeps with a different colour from their previous born colour, breed these two sheeps and you get a sheep that inherited the colour you dyed its parents), accidents of the Early Slimes accidentally ingesting these blaze materials or these blaze materials sticking onto the slimy skin of the Early Slimes can easily happen and be easily inherited to their offsprings. Generations whose ancestors obtained the material, could easily use the inherited materials as an advantage to develop more fire resistant skin, and become more successful in such fiery environment.

It's not surprising that these Organisms of Overworld Origin evolved and became more and more alien and unique from Overworld Creatures, because the conditions in the Nether are different from that of the Overworld's. But these organisms still retain some core traits from their Overworld ancestors, traits that make them a bit familiar to us Overworld Creatures.

TL;DR: Most of the known Nether Life originated from the Overworld through naturally-occuring portals. While a few known lifeforms are unique and are not of Overworld Origin, but are completely nature to the Nether. Some factors and differences exclusive to Minecraft Universe, helped the Organisms survive and become successful in the Nether despite the hostility of its environment.

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