That example classifies as a silly hypothetical, a joke, sarcasm, and a satire.
satire: "(
uncountable) A
literary device of
writing or
art which principally
ridicules its
subject often as an intended means of
provoking or
preventing change.
Humor,
irony, and
exaggeration are often used to aid this."
joke: "Something said or done for amusement, not in seriousness."
hypothetical: "Based upon a hypothesis; conjectural [quotations ▼] (philosophy) conditional; contingent upon some hypothesis/antecedent"
sarcasm: "(
uncountable) Use of
acerbic language to
mock or convey
contempt, often using
irony and (in speech) often marked by overemphasis and a sneering tone of voice."