Secret of the evil water monster

[Mekose]

Well, the true origin of the "Water Horror" is revealed rather late game. I believe you find a note in the "Nave"

Spoiler below!

Agrippa's main room

It was written by Johann Weyer, explaining that the Water Horror is from the dimension of the dead. So, it's actually a dead spirit or ghastly beast from the beyond that cannot be seen by normal human eyes. So, it truly is whatever your worst nightmare is.

Spoiler below!

Weyer explains that he needs to open a portal to the other side and trap the beast in a water well to extract it's mucus in order to create the tonic to save Agrippa. Here is the note http://img831.imageshack.us/img831/2499/kaernk.jpg

Correct me if I'm wrong.