How formal should the dedication section in a master thesis be? I want to make a little practical joke in the dedication of my master thesis. It's nothing extraordinary, and it's harmless, but it is all but formal.

I searched around and found this answer that states, as I already thought, that the acknowledgements section is not so formal and I can write it the way I want, but in terms of the dedication, it doesn't state anything.

Will the academia receive it well if I make this little practical joke in the dedication page, or should I write something a little more formal?
You could wander to your department library and check the dedication page of several master's theses to see what other students have done. 

In my case the department keeps a copy of every MSc and PhD thesis ever produced by students in the department, and they are available in the department library. I looked at a couple dozen. Most of them had some happy little thing like a line of poetry or something. A student who finished during my course work put the following on his dedication page.

One and One make Three

That's because he and his wife had a child during his grad work. On my PhD thesis dedication page I first gave a gushy thanks to my supervisor. Then I included a quote from Yoda, and a quote from a song by the music group Queen. 

I think as long as it's generally not nasty it will be OK.

You can also get some general ideas about format, writing style, citations, etc.  Maybe the people who did the binding will have left little notes in the cover so you can find out where to get that done. 

And, hey, the content might even be interesting.