Theory:

     VIJAY Singh picked up a piece of rock from the sand. “Take this,” he offered it to the ghost, “and squeeze it hard. It is filled with fluid. See if I am wrong.” While the ghost tried to squeeze the rock first with one hand, then with both, Vijay Singh stealthily took out the egg from his pocket.
 
     Vijay Singh snatched the rock from the ghost and placed it between both hands and squeezed. At once the yellow yolk oozed from around his fingers, and the crackling of the egg-shell created the illusion of the stone being crushed. The ghost was so astonished he did not notice Vijay Singh bending to clean his hands with sand and disposing of the tell-tale shell. Vijay Singh then picked up another piece of rock and gave it to the ghost. Without a word the ghost took it, felt it, and peered at it. Vijay Singh put his hand into his pocket to take out the lump of salt.
Explanation:
 
Vijay Singh had an idea. He decided to play a trick with the ghost. He wanted to prove that the ghost was inefficient and weak. He then picked up a piece of rock from the sand below. He gave it to the ghost and asked it to squeeze it hard. He informed the ghost that it was been filled with fluid. The ghost trusted him. It tried hard to press and squeeze the rock, but it couldn't. After all, it was a real rock. And during this time, when the ghost was busy handling the rock, Vijay Singh took out the egg given by the old woman. He did it without the ghost's notice.
 
Then, Vijay Singh pulled away the stone from the ghost. He kept it in between his hands and squeezed it. And, as expected, yellow yolk oozed out from his hands. The crackling sound created an illusion of a stone being crushed by Vijay Singh.
 
Vijay Singh's power.jpg
Vijay Singh's power
 
The ghost was amazed. It was surprised and shocked to see him breaking such a hard stone, without knowing its an egg.
 
Vijay Singh then bent down to dispose of the egg-shell carefully without the ghost's notice. It was so dark that the ghost thought that Vijay Singh had bent down to clean his hands. It didn't notice him hiding the egg-shells in the sand.
 
Vijay Singh hadn't stopped but had switched on to another plan. He took another piece of rock and gave it to the ghost for the second time. The ghost took it, felt it, and was deeply looking into it. Again, Vijay Singh planned to cheat the ghost. He made the ghost engaged in examining the stone; and while it was doing so, he took the lump of salt from his pocket.
 
Meaning of difficult words:
 
S.No
Words
Meaning 
1.
Squeeze
To press something with force
2.
Stealthily
In a way that cannot be seen or heard
3.
Snatch
To pull away or taking something, often in a rude way
4.
Ooze
To leak through small openings
5.
Crackling
A series of sharp sounds
Reference:
National Council of Educational Research and Training (2006). A Strange Wrestling Match: Indira David (pp. 43-51). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.