So,
Let's say that 3 friends have 5.000.000$ in bitcoins (or what ever coin of this value)
and they want to ==double== it in one day...

So, they find a small coin (like let's say shitcoin) which has a really small price (let's say 0.000004$)
And they buy for 8 hours like crazy.
This is going to make the price of the coin they invest get lets say 1000% up.
Plus all other people say: "this coin is going up! maybe is the next bitcoin! Lets buy!"

At the point that shitcoin reach 1000% (at let's say 0.000040$), 
the three friends have finally bought 5.000.000$ of shitcoins
from 0.000004 to 0.000040 // at the average price of 0.000015$
After that (yes you guess right)...
they start selling, to all the people who think that shitcoin, this is the next bitcoin
And they sell at the average price of 0.000030$

And this is how you double your 5.000.000$ in one day.
Pretty simple, isn't it. It happens all the time to real stock market places.