In this episode - not a spoiler - Don's son is playing in a swimming pool 'Daddy I'm gonna be a Shark!' and Don jumps over him. Or does he? Steady on chaps, it's only season 4; hold your nerve.
Don's creative pitches were a major feature of seasons 1-3, but there have been very few in this one. Here is a transcript of his pitch to the American Cancer Society, from whom he is hoping to get a contract to produce a series of anti-smoking adverts. This advert is aimed at teenagers.
'Show mothers and daughter, or fathers and sons, and that cigarettes are between them, and show, with a walk on the beach, baking cookies, playing catch, that the parents are not long for this world.'
'But they hate their parents.'
'They won't be thinking about their parents. They'll be thinking about themselves. That's what they do. The truth is, they're mourning for their childhood more than they're anticipating their future, because they don't know it yet but they don't want to die.'
Not to belabour the point, but who are 'they' and what is this poisonous addiction that spoils all communication? For a start they are us, watching a TV show about our parents, but thinking about ourselves.
Other than that, I would say this season does not end on a high or a surge of power, instead petering out in confusion, self-destruction, and mistakes, in which all new chances and fresh starts seems to be spoiled before they have even begun.
The episode ended with the song that is repeated endlessly in Groundhog Day - 'I've got you Babe', by Sonny and Cher: that sinister droning elegy to a doomed relationship. It is an allegory for an endless futile cycle in which rebirth is a curse not a blessing.
*though Vince Gilligan, of Breaking Bad, wrote an X Files Season 9 episode called 'Jump the Shark'