First, they started with the decorator worm. A unique animal that the child had plans for.

Grabbing a five-centimetre-long ice mana string, the child rolled out a perfect sphere into the palm of their hand. The sphere, coming out to be a centimetre in length, was light blue in colour, and the child was ready to start this process. Placing it into a decorator worm and sewing it in place with their own mana string, the child waited for the change to happen.

Minutes passed as the ice core was placed within the worm before they began to change.

Growing to 75 centimetres long, the worm's colours shifted to light blue, almost the same colour as the pressurized ice stalactites and stalagmites. With the lengthening of the worm, the defence mechanism of the worm changed. No longer collecting sand, debris, and shells, the worm adapted its defence by gaining thick but flexible interlocking scales that covered them head to tail. The jaws and teeth of the worm also shifted. From large sharp jaws, the worm gained two sets of crushing plates for teeth. It is also a great ice-digging tool designed to latch on and crush whatever is in its mouth.

They gained a small ability to manipulate ice from the ice core but not pressurized ice.

You have made a new ice elemental species. Please name and register your species.

Waiting to see what the elemental worm would do, the child held off on naming it just yet.

It swam around the first room of the floor before choosing one of the thickest stalactites to make its home in. The worm slowly carved a small path into the stalactite with their ice-carving jaws. Once fully in the stalactite, the worm used its limited ability to cover up the entrance to its home. Effectively camouflaging themselves into the stalactite.

Seeing how the worm used its ability and where it chose to make its home, they decided to call it the stalactite worm.

You have created the ice elemental species "Stalactite Worm."

The child created more ice cores and sewed them in ten more decorator worms. Once they made the transformation into an elemental species and chose their new homes through the floor, the child moved on to the next animal.

The next creature that they chose to work with is the red-tentacled box jellyfish.

Cutting a five-centimetre long piece off the frigid mana string, the child made a small, just under a centimetre wide frigid mana core that they placed within the jellyfish's hood.

After a few minutes passed, the jellyfish started changing. Growing from a box-shaped to a larger half-sphere dark blue hood, about thirty centimetres long and wide. Long tentacles and arms multiplied and grew from the hood. All of the tentacles and arms were completely transparent in the water; the only thing visible about the jellyfish was the dark glacial blue colour of the creature's hood.

Taken from Royal Road, this narrative should be reported if found on Amazon.

It was within the jellyfish's arms and tentacles that held a part of the frigid mana core's power. Each of the ten long tentacles had the ability to just cool down their internal temperature to well below freezing, and it is just the tentacles. Anything living these tentacles touches when they are using this temperature manipulation will turn the water within the affected area into ice crystals, causing severe bodily damage and even limbs cracking and falling off. And this was not the only way that the frigid mana permeated the jellyfish.

Along the arms of the jellyfish were stingers that have a tiny bulbs that have a coiled, sharp-tipped tube containing venom. Well, not so much venom. The red-tentacled box jellyfish's venom became infused with the frigid mana when the jellyfish started shifting, creating a new type of venom. Along with blister-like wounds, the mana-infused venom also produced a spreading freezing effect. The more contact that the venom had on flesh, the more the freezing effect will spread.

You have made a new frigid elemental species. Please name and register your species.

Letting the jellyfish leave their grasp, the child watched as it slowly drifted across the rooms with the current. As it drifted, they began thinking of names, and after an hour, they found the perfect name for it.

You have created the frigid elemental species "Gelid Jellyfish."

Populating the floor with just enough frigid cores to create enough gelid jellyfish to be encountered but not in abundance.

Choosing the grey oyster as their next potential elemental species, the child got to work.

Taking a 20-centimetre-long water mana string, the child rolled it down into a tight sphere, just under two centimetres long.

Placing and sewing the core into the oyster, the child took a step back and waited for the changes to come.

The oyster grew to be 20 centimetres long and 10 centimetres wide, and it stayed the same grey, oval shape as it was before they sewed in the water core.

While the oyster may have kept the same general appearance that it once had, that did not mean that there was no effect from the water mana.

The oyster itself became a lot more protective and defensive of itself. While normal appearing, once the oyster is disturbed, it creates a quickly slamming dense water force at whatever intrudes into their direct space. The hinge mussel of the oyster, the muscle that keeps the oyster shut, gains the ability to suction cup the shells of the oyster together and internally cover the shells with a hard watery fluid that will fill in any cracks on the shells.

You have made a new water elemental species. Please name and register your species.

Letting the oyster settle on the ground, the child flicked away the blue screen and started thinking about names.

But they noticed the oyster doing something before they could even settle on a name.

Looking carefully at it, the child watched as the oyster seemed to carve a tiny portion of the string from a nearby circulating water mana string. The oyster pulled it into themselves and started a process that looked very similar. It basically replicated the child's process in creating different types of cores.

But, as they watched, they realized that the oyster was doing it differently.

More slowly.

They could see the mana string being added around a small speck of debris within the oyster. And as the oyster secreted layers of minerals around the debris and mana.

The child watched this process for over an hour before it led to the results.

The oyster used the debris, minerals, and mana to make a single, somewhat rounded cream-coloured sphere with a luminous blue shine to it.

After seeing the results, the child named it the Nerite oyster.

You have created the water elemental species "Nerites Oyster."

The child created more water elemental cores and threaded them throughout some of the grey oysters.

Each Nerite oyster was hidden within the grey oyster population, hoping to help camouflage them.

Just as the child was about to figure out what they were going to do next, they were startled out of their revelry by a tapping on their core.