Mandragoras are soil-dwelling, plant-type monster girls. They don't go around actively raping humans, but rather use a combination of an attractive fragrance and a psychoactive scream to induce men to rape them.
In the Monster Girl Encyclopedia World Guide II: Demon Realm Traveller's Guide there is a whole section on mandragora's roots, which can be painlessly harvested to use as an ingredient in cooking and aphrodisiac potions. Mandragoras also like having these roots sucked by their husband, so they're good for root fetishists.
A plant monster in the form of a woman with roots. The parts corresponding to the roots are buried deep within the earth. They only push out the flower on their head to the surface of the ground. They wait for their prey, which is lured by the sweet fragrance released from the flower petals, to come and pull them up.
When a man uproots them, they let out shrill screams containing magical power. Those who have heard such screams will temporarily lose their ability to reason. Guided by instinct, they will likely sexually assault the mandragora before them. When a man starts having sex with them, they use their roots to wrap around him so that he cannot escape later. Even after the man’s ability to reason returns, he probably would not be able to get away until he gives his seeds. If the man refused to move his hips, they will move the roots coiled around his waist to crash his hips into their own.
Because their screams not only affect the man who uprooted them, but also other humans and monsters nearby, when approaching an area inhabited by mandragora it is necessary to be careful of screams coming from out of nowhere, and monsters that went mad and turned ferocious as result. Of course, a man who uprooted one would also be attacked by other nearby monsters, if they are present.
Furthermore, once they are uprooted and they let out their scream, they lose most of their magical power so that even if they scream after that it would not cause anyone to lose their reason.
In this way, they are powerless once uprooted. Since they have extremely timid personalities, they almost never attack humans on their own.
Also, the tips of their roots are treasured as ingredients for stamina increasing drugs, aphrodisiacs, and many other powerful magical medicines. Because these parts continue to grow as they are fed semen, it is not uncommon for people to raise them.
During their larval stage, they are buried within the earth. Absorbing nutrients from the soil, their bodies are formed. The growth of their body stops once they are pulled from the earth. For this reason, the sooner a mandragora is uprooted the more childish her appearance will be, as in the illustration. Likewise, the later a mandragora is uprooted the more her appearance will differ from the illustration, instead having a more voluptuous figure.