You're not walking around naked, so why would your water bottle be exposed to everyone's prying eyes? That *seems* to be the logic behind these bottle panties, launched in Japan in late May by novelty goods producer Kitan Club.
Sold via vending machines, bottle panties, or bottle underpants (depending on your translator), cost a meager 200 yen ($1.6) and come in a variety of designs, including strawberry, polka dot and leopard print, as well as a secret design.
A typically Japanese product, bottle panties remind us of the equally cute smartphone panties, which made the rounds in 2013 and seemed similarly useless. Kotaku, however, notes that the bottle panties might actually have a purpose -- they catch beads of moisture which appear on the bottle surface if the drink is cold, preventing them ruining your table.
As for size, you'll only be able to dress up your 500ml bottles; sorry if that leaves your 2L bottles naked and embarrassed.