2014-08-04
Explanation
The Joke
A woman is enthusiastically declaring "HAHAHAHA! SEE! YOU SEE MY POWER?! I'M LIKE A WIZARD!" while a bespectacled woman responds with a flat "Uh huh." The caption below reads: "Fun Fact: Saying 'I SUMMON ENTROPY' actually creates entropy."
The comic appears to be the punchline of a longer joke (possibly a multi-panel strip where earlier panels are not shown, or the setup is implied). The woman seems to have demonstrated some trivial or obvious outcome and is claiming credit for it as though she has magical powers.
The Humor
The joke works on multiple levels. The "Fun Fact" at the bottom is the real punchline: saying "I SUMMON ENTROPY" does technically create entropy, since speaking requires energy expenditure, which increases the overall entropy of the universe. This is a play on the second law of thermodynamics -- any action, including speech, increases the total entropy of a closed system. So in a trivially true sense, shouting "I SUMMON ENTROPY" is a spell that always works, making you technically a wizard.
The humor comes from the gap between the grandiose claim ("I'm like a wizard!") and the mundane reality that literally everything you do creates entropy. The other woman's deadpan "Uh huh" perfectly captures the appropriate level of being unimpressed by this "power."
References
The second law of thermodynamics states that the total entropy of an isolated system can only increase over time. Any physical process, including the act of speaking, converts ordered energy into heat and sound, thereby increasing entropy.