My young filmmaker friend asked me if the word 'education' was correct in the following preview subtitle: The dietary education of the aliens, meaning that the aliens are going to set about learning what humans eat. The film is humorous, not serious; as far as I can tell, it might qualify as a spoof.

I said that word is perfect, because it juxtaposes something that is usually a serious subject with one that is usually not. (I don't know, but am guessing that by the time viewers see this they will have also seen how silly the "aliens" look.)

My question: isn't there a word or term for this juxtaposition in either a theatrical or literary setting? A name for this specific technique, as it were?

I would say the aliens made a study of human diets.

Probably some version of irony.

I was thinking irony, yes, thank you. But isn't there some word or phrase for when this kind of thing is used deliberately as a...gimmick, or lure, to pique the audience's interest?

A hook?

Yes, that's accurate, thanks, but still not what I'm looking for. Maybe I was mistaken; yet I thought there was a term--other than irony--for when the serious is deliberately juxtaposed with the humorous. Perhaps I shouldn't have tied it so closely to theater.