There is no way to find the square root of a negative number. It just doesn't work. So the answer to the impossible question, "What number squared equals a negative number?" is just said to be $i$, an imaginary number.
So now let's look at a different problem. What is one divided by zero? Of course, you can't answer that question. It doesn't make any sense. Splitting up a chocolate bar to a group of 0 friends isn't possible. It's like being told to walk north when standing on the north pole. So, what if just like $i$, we just say $1/0$ is an imaginary number, referenced by the letter $o$?
What applications would this have? Does it even work? The number $i$ has real life applications, but it can also be used to create abstract designs like the Mandelbrot Set. Could $o$ even be used for an abstract purpose?