How Shoggoths (may have) started life on Earth

In the Cthulhu mythos, the origin of life on Earth was the result of the Elder Things' creations- the shoggoths. I was working on an ooze-ooze aggregate idea for Mutant Future and have come up with an idea on how shoggoths may have spawned other life. Aggregates are organisms that are made up of two or more species that are fusing into one. This is a real world concept- some cellular components, such as plant plastids, are an example of this.
 
I was working on a black pudding consuming a crystal ooze, an aquatic version of the grey ooze from the first or second edition of AD&D. The ooze becomes something like organs within the pudding, ones that can split and merge, thus allowing for multiple weak mutations or a few strong ones when the pudding needs them. When the whole splits, each daughter pudding takes some of the ooze with it. They go through evolution, adaptation and MF style mutation. Every time the pudding or ooze mutates, it has an impact upon the other. In this case, the pudding becomes marine, using the ooze as a gill of a sort. Other mutations that the ooze might gain to become more useful to the whole include chemical gland (tapping into the amazing number of raw materials in sea water), energy-retaining cell structure (the ooze becomes a second skin and produces a charge that zaps everything near the pudding) and drone (little oozlings that split from the whole and then merge with it again).
 
It is drone where things can get very interesting. Primary drones are little oozes. If they mutate themselves (i.e. seperately from the pudding-ooze aggregate), they can become secondary drones- flesh and blood organisms with tissues and organs. A pudding could contain several kinds of secondary drones that act as organs as well as extra-ooze creatures that perform actions such as scouting and hunting. If a pudding/ooze was to die when several of its drones are outside it, those drones might survive and if they are of the same type, breed. They would be new species. Put them through the family concept from Creatures of the Wastelands: Mutational Evolution, and one could get dozens or even thousands of new species all that exist because a black pudding was near some water and "ate" an ooze.
　
For those who want to try this out with non-oozes; fungi, worms or even tiny elementals could invade plants and animals, infest certain organs or tissues and, with something like the drone mutation, create entirely new species unlike anything else on the planet.
　
Shoggoths are massive oozes that were created to perform any task their creators wanted. If they needed to make drones, they could. The first plants could have been drones meant to collect local energy sources. The first animals could have been drones that escaped control, probably just before the shoggoths rebelled themselves. And, as there still are shoggoths on mythos Earth, that means they might still be spawning off new species...
　
While thinking about this, I also wonder can the living d20 creature types evolve into each other? I don't mean could a dog evolve into a rose, but rather a dog evolving into a creature that has all the plant traits. What would an ooze or a plant decended from dragons look and act like? I would actually expect this from settings like Epidemic's Oathbound, where magical evolution of characters and monsters is central. But I am not sure if it should be possible in other settings like the Realms and Iron Kingdoms.