“Mind flayers unleash all manner of foul experiments upon the planes with little thought for the consequences. Here, though, I suspect another influence: Juiblex.”
“An oblex wants memories, but not to serve any end of its own making. Oblexes are hungry for memories and personalities because they are empty without such nourishment. In this way they serve their creators, the illithids. An oblex in the range of an elder brain's powers provides everything necessary for the mind flayers to find choice victims.”
By experimenting on the slimes, jellies, and puddings that infest the depths of the Underdark, mind flayers created a special breed of Ooze, the oblex—a slime capable of assaulting the minds of other creatures. These pools ofjelly are cunning hunters that feed on thoughts and memories. The sharper the mind, the better the meal, so oblexes hunt targets more likely to be intelligent, such as wizards and other spellcasters. When suitable fare comes within reach, an oblex draws its body up to engulf its victim. As it withdraws, it plunders the creature's mind, leaving its prey befuddled and confused—or dead.
When oblexes feed on thoughts, they can form weird copies of their prey to use as lures, which helps them harvest even more victims for their mind flayer masters.