abduction
Explanation
The Joke
A man is telling a woman that he believes alien beings abducted him and had sex with him. The woman challenges this claim by pointing out the absurdity of the premise: aliens who traveled from far across the galaxy, with vastly superior technology and intelligence, possessing deadly interplanetary weapons, somehow found this particular unremarkable human to be the most attractive species they had encountered. She notes they could have chosen an Olympic athlete, a great beauty, or a head of state, but instead supposedly picked him.
In the third panel, the man protests that when she puts it that way, it sounds "even more likely" -- completely missing (or ignoring) her point that the scenario is absurd. The woman then asks if he has any self-esteem books he'd be willing to sell, implying that his eagerness to believe he was chosen for alien sexual attention reveals profound self-esteem issues, and that he clearly no longer needs those books since his self-esteem is apparently sky-high.
The Humor
The comedy works on multiple levels. First, there is the classic comedic setup of an alien abduction believer being confronted with the logical absurdity of their claims. But the real punchline is the inversion: instead of the man being embarrassed by the logical takedown, he takes it as further confirmation, revealing that his belief is rooted in a desire to feel special. The woman's closing jab about self-esteem books ties it together -- she recognizes that anyone who can convince themselves an advanced alien civilization found them sexually irresistible clearly does not suffer from low self-confidence.
References
The comic plays on the well-known cultural trope of alien abduction stories, particularly claims of sexual experimentation by aliens, which became prominent in UFO culture from the mid-20th century onward. The Fermi Paradox and questions about why hypothetical advanced aliens would be interested in humans at all are also subtly referenced.