Samal's mind burned.
It had been two days since he had discovered the veins of energy crossing his underground stream, changing and twisting the fishlife and filling it with Neshara's blood. The fish had grown in size unbelievably fast, drinking the raw, divine energy. He had simply studied them at first, wondering about the appearance of the veins. Nothing interesting had happened to his little stream, hidden from mortal eyes deep underground, before.
Then he had made the mistake of drawing in some of the energy.
It had felt wondrous at first - every fibre of his being filled with new, incredibly strenght. His senses had become much sharper, his control of the river much simpler. Overjoyed at his new life, Samal had descended upon the veins and started drinking, pulling more and more of the amazing energy into him. It had tasted so much like blood.
But he was no mere animal. The fish were simple of mind already, but Samal was a higher being, a water spirit of Lord Amparos.
The more of the raw magic of the veins he had devoured, the more alive he had felt, his body burning with unseen flames. After a while, the fires had become entirely too intense. They were physically hurting him, his entire being feeling like it could explode at any moment. But Samal had kept drinking, unable to stop himself.
When he finally had been able to wrench himself from the veins, he could no longer see, or feel his river below. His body glowed with visible light, bringing illumination the dark caverns for the first time ever. The pain had been overwhelming.
It had only grown worse with time. Without his vision, he could no longer find the veins, and quench his thirst. He held onto the last fragments of his mind desperately, but the fires were relentless. He was fighting a losing battle for his mind, his sentience fading with every passing moment.
In the end, there was nothing he could do. His thoughts now barely above an animal's, Samal let go. The raging fires of divine energy found the last stronghold of resistance in his mind and overran it. Now an empty husk, Samal collapsed upon the stream's shore.
What stood up from his remains was no longer a graceful spirit of the rivers, nor a sentient being at all. Born of blood, it hungered for more to sustain itself. The beast resembled Samal with it's humanoid form, but it's body was quite solid, stone from the cavern floor intervowen with flowing, red-coloured waters. Mist-like crimson tendrils appeared from it's upper body, created for killing it's prey and drinking their blood only.
Mindless, the thing began to crawl down the cavern floor, tendrils feeling the ground around it for sustenance.
A water spirit is transformed into a mindless beast due to overexposure to Neshara's blood