Theory:

Mushroom rock or pedestal rock: As the name suggests, the shape of the rock will be in the shape of a Mushroom. This shape of rocks is mostly seen in deserts because the wind carrying sand erodes the lower section of the rock more than that of the upper part. This is because the speed of the wind is higher close to the surface of the earth.
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Mushroom rock
 
And this can also happen if rocks are made up of a hard top layer and soft bottom layer. When the sand-laden winds blow against it, wears. By the constant action of wearing down, the bottom gets eroded away to form a mushroom-like structure. Such rocks are found near Jodhpur in Rajasthan.
 
Inselberg: Inselberg is a German term that means an island mountain.
Inselberg is a small, rounded hill, knob, ridge, or mini-mountain that rises abruptly from relatively flat surroundings. It is also called a monadnock.
E.g. Uluru or Ayers Rock, Australia and Inselberg in the Kalahari desert of South Africa
 
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Inselberg
 
Yardang
An elongated erosional landform, commonly found in arid regions, where certain rocks have hard and soft layers arranged vertically in the direction of the wind. When winds blow over these rocks, the soft layers get eroded, leaving irregular crests. These are called yardangs.
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Yardang