A cartoon dog drawn by Inugami Korone, originally part of her autograph and treated the same way as Hoso-Inu it eventually became it's own character in April 2021 when Korone realized that she originally used to draw Hoso-inu differenly, so she just named the old-style "Futo-inu" and started to include it on her streams.
The main difference between Hoso-inu and Futo-inu is the shape of their snouts. Futo-inu has a wide snout while Hoso-inu has a narrower, straight snout. Futo-inu also has black floppy ears while Hoso-inu has white ears.