So WTF is a Towelkini? Short answer: It is a terry-cloth towel and bikini combined into one handy item of clothing.
OK, but why does the Towelkini exist? As you may have already guessed, the Towelkini is not a particularly practical item, despite its two-in-one nature. It's actually a piece of art by Aria McManus created for an SPF-themed exhibit at Special Special, a design store in New York City. And while it was originally conceived as a fun art project, you can in fact purchase one for yourself to the tune of $199.
If someone did want to wear one, what would that look like? Although it's advertised as a bikini-esque item, the Towelkini does not provide full coverage, meaning you'll definitely have to wear a bathing suit underneath—unless you're OK with showing your backside or full-frontal situation with everyone at the beach or pool. But it is reversible and can be worn either as a sort of weird poncho-cape combo that exposes your front or as a backless kaftan (two things you definitely never realized were missing from your wardrobe).
So, uh, if it's not really meant to become a beach vacation staple, why do we care so much? To borrow a phrase from Charles "Chazz" Michael Michaels, "No one knows what it means but it's provocative." The specific level of ridiculousness and provocation achieved by the Towelkini speaks to us in a way that the impossibly small Mini Le Chiquito by Jacquemus or bridal Crocs simply never could. Either that or we just needed to have a good laugh on a Wednesday afternoon.