Hax left after his little experiment. He had tried to dirt, rocks, iron, and wood on the black pus, but it only reacted to water.
That was something important to ponder. Why did they only react to water?
Water was almost the key to life in every universe. Back in the Human Universe, every alien that borned there at least had some percentage of water in their body. And that was also the same for the majority of the multiverse.
The reason for that was because water was capable of dissolving other substances to create a chemical reaction. Basically, it let a variety of elements mixed themselves together and became something that could be called 'alive'.
So essentially, water was the core substance of life. Without water, there would be no life.
With that consideration, it was highly probable that the black pus was programmed to kill every living being in this world by removing the most essential elements for life to exist.
Water.
