Witch's Grudge

Mixed into the solitary river surrounding Ansa Thalas that connects to the sewer systems of Avalon Logging and the wells of Ansa Thalas, the Witch's Grudge is a failed experiment that wasn't properly disposed of. As it mixed with the fresh water of the river, its original color became diluted, eventually running clear and making the water appear safe to drink. However, the liquid does smell like caramel, which passes onto the water as a very subtle aftertaste.
  The virus is easy to mix with other substances, especially water. Even though the color dilutes when mixed with something, the virus stays strong, acting under a camouflage of water.

Creation

It is a virus created by Dr. Kazeqxik, who works for Captain Vaunea. After virus failed to work with the experiments, Dr. Kazeqxik had the virus dumped into the sewers to get rid of it, thinking the harsh environment of the sewers would prevent the virus from mutating into something more dangerous.