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Explanation
This comic depicts two characters made of electromagnetic radiation (photons or EM waves) nostalgically discussing changes in the electromagnetic spectrum.
One character says: "Hey em, have you ever seen a seriously deep cut of cosmic radiation?" The other responds with alarm: "!?" Then: "Why do you ask?" The first replies: "I just used to see them all the time."
In the next panels: "We used to all have maximum wavelength oscillation. Now all I see is IR." Another character interjects: "Wait a minute..." and the punchline arrives as we see a photon being redshifted — stretched out — as it travels through expanding space. The visual shows the character literally being pulled apart.
The comic personifies electromagnetic radiation to make a joke about cosmological redshift. In an expanding universe, photons traveling through space get "stretched" as space itself expands, increasing their wavelength and shifting them toward the red/infrared end of the spectrum. This is the mechanism behind Hubble's observation that distant galaxies appear redshifted.
The characters' nostalgic conversation about how they "used to see" high-energy cosmic radiation "all the time" but "now all I see is IR (infrared)" is a photon's-eye-view of the universe's expansion. What they're experiencing as a cultural or demographic change is actually the physical process of cosmological redshift stretching all the photons to longer wavelengths over cosmic time. The final panel, showing a photon being physically elongated by expanding space, makes the mechanism explicit and serves as both the explanation and the visual punchline.