Hoppa i poll or Hoppipolla?

So, I am planning to get a Hoppipolla tattoo. Very simple, just the one word. Nevertheless, after looking for the lyrics to get the spelling correct, it is my surprise that in some lyrics is written "Hoppa i poll" and in other ones is written "Hoppipolla". What is the difference? If I would get "Hoppipolla" will it be gramatically correct? Please, avoid the "who cares if it is gramatically correct", I care.