skills
Explanation
The Joke
A father figure confronts what appears to be his daughter's boyfriend or suitor. He begins with the classic protective-dad trope: "You'd better treat my daughter right, because let me tell you..." But instead of threatening violence or listing intimidating credentials, he reveals he has "a very particular set of skills" -- a direct reference to Liam Neeson's famous monologue from the movie Taken (2008). However, the "skills" turn out to be entirely non-threatening: he can "conjure boogers in his nose and a pirate's mustache," he draws "comic strips," and he "cannot antagonize many stink-lines." The suitor simply responds with an awkward "Okay, sir."
The Humor
The comic subverts the "protective father" trope by setting up the Taken reference and then deflating it completely. In the film, Bryan Mills's speech is a menacing promise of extreme violence from a former CIA operative with lethal combat abilities. Here, the father's "particular set of skills" are embarrassing, irrelevant, and completely unthreatening. The humor comes from the anticlimax: rather than being intimidated, the suitor is just confused and uncomfortable.
This is also a self-deprecating joke by cartoonist Zach Weinersmith, as the father character appears to be a stand-in for Weinersmith himself -- a comic strip artist whose threatening capabilities are limited to drawing unflattering cartoons. The "boogers in his nose and pirate's mustache" is a self-roast about his own appearance or art style. The joke functions simultaneously as a parody of overprotective-dad culture, a movie reference subversion, and an artist's self-deprecating admission that his actual skill set is about as intimidating as a damp tissue.