Yochlols are fictional demonic creatures in the Dungeons & Dragons fantasy role-playing games, having been first introduced in the first edition Advanced Dungeons & Dragons: Queen of the Demonweb Pits in 1980.
They appear as tentacled blobs of melted wax and continually emit a foul stench. Yochlols also have the power to change their shapes, usually to a comely drow female or to a spider (usually a black widow). They can also change themselves into a gaseous form, allowing their unknowing victims to inhale them, and then suffocating them.
It is possible that they originate as the souls of high priestesses of Lolth who died in the favor of their goddess.
Their main purpose is to establish a mental connection to the high priestesses of Lolth, scouring their thoughts and memories to find proof of their loyalty and dedication.