We would call this an inside joke, but we're not even sure if there are enough people "inside"
You may think you're special for getting the joke on this shirt, but do you realize HOW special?
Of all the observed universe, only the Earth is known to have supported complex life.
Of the living organisms on Earth, only a relatively small fraction (the Radiata) have central nervous systems.
Of the animals with central nervous systems, only a relatively small fraction (mammals, some birds, some cephalopods) are capable of conceptual thought.
Of the animals capable of conceptual thought, only a handful (humans, chimpanzees, possibly dolphins) are capable of linguistics.
Of the animals capable of linguistics, only humans are capable of abstract problem solving.
Of the seven billion humans alive today, only a small fraction speak English and know that "ma" stands for "mass times acceleration," which represents "force."
Of this tiny fraction, only an even smaller fraction are familiar with the fictionalized universe of the "Zelda" video game franchise.
And even of this tiny, tiny, tiny fraction of all the organisms on Earth, only some are capable of figuring out the joke, even when presented with it.
Now do you feel special?