oil
Explanation
The Joke
A group of business or political figures are discussing the problem of young people not buying cars or gasoline. One person notes that young people are instead using electric vehicles and mass transit, and that the petroleum dollar is in decline. Another suggests they need some way to rebrand gas stations to appeal to modern sensibilities. The "solution" revealed in the final panel is a gas station with a sign reading "Essential Oil of Shale Sold Here," and someone exclaiming "Ooh!"
The joke is that the oil industry's answer to declining demand is not to adapt their actual product, but to rebrand petroleum using the language of the wellness and essential oils movement. "Essential oils" (like lavender, eucalyptus, etc.) are hugely popular among a certain demographic, and "oil of shale" (shale oil) is literally just petroleum extracted from shale rock formations. By slapping wellness-style branding on fossil fuels, the comic imagines a hilariously cynical marketing ploy.
The Humor
The comic satirizes both the fossil fuel industry's resistance to change and the gullibility associated with wellness culture marketing. The phrase "Essential Oil of Shale" is a perfect linguistic bridge between two very different worlds -- the crunchy, health-conscious essential oils community and the dirty, industrial world of petroleum extraction. The final "Ooh!" from a customer suggests the rebranding would actually work, adding an extra layer of cynicism about how easily consumers can be swayed by trendy packaging.