Witches made alliances through illusion and reality, then used the alliance as a stepping stone to utilize the magical powers of nature. They could also use their dreamland as a way to train, so they would have this terrifying ability to be much more powerful when they returned to reality.
Even in reality, when they encounter an inevitable crisis, witches could make use of their alliances' power to enter into their dreamland and avoid any danger. It was something similar to avoiding death through teleportation, which was the principle of the Broken Lizard Tail method that Nasira used previously.
However, that monster's fluid was still sticking onto Nasira, and even after she entered her dreamland, she was not able to completely get rid of it. It was horrifying because this meant that the tentacle monster's fluid had a certain degree of spiritual energy polluting toxicity.
