Exponential DK.
Explanation: This joke is a play on words combining the character “Donkey Kong” (often abbreviated as “DK”) from video games with the mathematical term “exponential decay,” which refers to a quantity decreasing at a rate proportional to its current value. The punchline, “Exponential DK,” humorously suggests that the gorilla’s size is decreasing exponentially, creating a clever connection between gaming and mathematics. The humor lies in the witty wordplay and the unexpected blend of concepts.