Abyssusfluid is defined as "a fluid gender that flows into sight and then quickly out of sight as soon as it is observed."
Abyssusfluid was coined on December 15, 2019 by tumblr user hawaiiaine (aka gendernovus, genderstalgia, genderpotion, exosphenic, genderrose, mason-the-owlkin, atergender, beysgender, mogai-minecraft-snail, polysexualtea, aresgoesgender, thepancherryblossom). The flag was created at the same time.