Horrorboros

Horrorboros is an upcoming King Salmonid that will appear in Salmon Run Next Wave during an Xtrawave. They are the second type of King Salmonid to debut in Splatoon 3.

Quotes
"We're probably legally required to inform you that a new type of King Salmonid may begin appearing in March. It's a giant, terrifying serpent called Horrorboros, and did we mention that it flies? But... you'll probably be fine. Remember - you can earn a sticker!"

- @SplatoonNA on Twitter

"A new King Salmonid has been sighted snaking through the skies in #Splatoon3! Witnesses are referring to it as ' Horrorboros ' ..."

- @NintendoEurope on Twitter

Etymology
Horrorboros is a portmanteau of "horror" and "ouroboros", an ancient symbol of a serpent or dragon that is eating its own tail.