The combination of the trickster planet mercury and the action-oriented mars creates someone who is really good at pranks and practical jokes.
When these two planets conjunct, they merge into one and turn into active wit or witty actions aka physical humor.
Individuals with this aspect can often be a sort of comic relief character.
They could be seen as having a "primitive" kind of humor because it's often just based around acting goofy and making a fool of yourself.
Although they aren't necessarily very witty in their jokes, they're really effective - because they make you laugh!
George Clooney has a Mercury Mars conjunction and you can look up his whole history of pranking!
Joseph Gordon-Levitt has the same aspect and was celebrated for his lip sync battle:
Louis Tomlinson, the king of practical jokes, debuted his physical humor career on the X-Factor and the video diaries of One Direction. He has the conjunction as well. You can read my whole chart analysis of Louis here.
Justin Bieber also has this aspect and egged his neighbours house a year ago or so.
Ashton Kutcher has the opposition and he was nothing less but the host of a show called PUNK'D which was dedicated to pranking people. How fitting.
Then there's the lesser known aspect of the quincunx aka inconjunct, which I have found to be actually pretty significant when it comes to these traits: Tyra Banks and Emma Stone have this aspect and they are very well known for funny faces, sounds or ways of acting.
Other traits of this aspectNext to the practical humor, this aspect also comes with a very aggressive way to express one's opinions and a proneness to heated arguments or verbal warfare, especially with the conjunction, opposition or square.
Mars is a very aggressive planet, always ready to pick up a fight and compete. Mercury being the planet of the intellect, this can indicate a sharp tongue and a fierce defense of someone's opinions.
It can also show competition with siblings.
These people combine words and actions - realizing their ideas practically and directly.