hazelnut
Explanation
The Joke
A scene at a coffee shop: a barista is about to ask a question ("But how did you know it was a--") when a man behind the counter, who is being held at gunpoint by a large bald man, blurts out "Hazelnut." The caption below reads: "Fun fact: Flavored coffee only exists to detect androids."
The Humor
The comic plays on the science fiction trope of using seemingly trivial human knowledge or sensory experience as a test to distinguish humans from androids (a la the Voight-Kampff test in Blade Runner or similar "are you a robot?" scenarios). Here, the test is absurdly mundane: identifying a hazelnut coffee flavor. The android apparently cannot identify the flavor, giving itself away, which is why the armed man is there -- presumably to deal with the exposed android.
The "fun fact" at the bottom elevates the joke by suggesting that the entire flavored coffee industry exists solely as an android detection system, which is a wonderfully absurd conspiracy theory. It implies that hazelnut lattes, French vanilla, and pumpkin spice are not consumer products but rather an elaborate, society-wide Turing test embedded in everyday life. The deadpan presentation of this as a simple "fun fact" adds to the humor.
References
The comic references the science fiction concept of android/replicant detection tests, most famously the Voight-Kampff test from Ridley Scott's Blade Runner (1982), adapted from Philip K. Dick's Do Androids Dream of Electric Sheep? (1968). These tests typically rely on emotional or sensory responses that machines cannot perfectly replicate.