Inkling

Inklings are creatures from the Splatoon series. They are a race of squid-based humanoids who live in Inkopolis, where they participate in Turf Wars in which they attempt to cover as much area as possible with their ink, along with other sports and activities such as Splatfests and Salmon Run. This link is a link to Inkipedia's article on Inklings.

Super Smash Bros. for Nintendo 3DS / Wii U
Inklings make a small appearance in Super Smash Bros. for Nintendo 3DS and Super Smash Bros. for Wii U as downloadable costumes for the Mii Fighters, which were released on June 14, 2015. The Mii Gunners can wear an Inkling Oufit which changes design based on the gender of the Mii, while any Mii Fighter can wear the Inkling Wig or the Inkling Squid Hat, the former of which also changes by the gender. A trophy of the Inkling Girl can be unlocked in both versions after players download the Inkling Outfit.

Super Smash Bros. (Nintendo Switch)
The Inkling Girl and Inkling Boy are set to appear in the upcoming Super Smash Bros. installment for the Nintendo Switch.

Super Mario Maker
Inklings appear as one of Mario's costumes in Super Mario Maker. There are three types of Inkling costumes: Inkling Boy, Inkling Girl, and Inkling Squid, the latter of which can assume humanoid form by holding up on a control stick. Along with being unlocked by scanning their respective amiibo, these costumes can be unlocked randomly by completing the 100 Mario Challenge.

The Squid Sisters also from Splatoon, consisting of Callie and Marie, make an appearance in this game as costumes for Mario.

Mario Kart 8 Deluxe
Inklings appear in Mario Kart 8 Deluxe. Players can select both the male and female versions of Inklings, as well as a variety of different colors. Like the multicolored Yoshis and Shy Guys, the color variations of Inklings cannot be used by the CPU drivers. They are equipped with their Splattershots and can turn into their squid form when performing a Trick. They come with their own themed battle course called Urchin Underpass, and have signature ATV bodies, the Inkstriker and the Splat Buggy; both vehicles are unique in that they spray colored ink from the exhaust pipes when getting a speed boost, instead of normal flames. This also marks the debut of the Inklings in the Mario Kart series. Their kart symbol is an Inkling Squid in the color of the character. Both are medium weight characters; the girl is in the same subset as Cat Peach and the female Villager, while the boy is in the same subset as Tanooki Mario and the male Villager.

One of Inkling Girl's animations was originally considered by some to resemble an ; it was later modified in Ver. 1.1.0.

Super Mario Odyssey
In the Balloon World minigame in version 1.2.0 of Super Mario Odyssey, the Inklings along with the Squid Sisters make cameo appearances on the balloons, as players are able to set them as their Nintendo Switch profile pictures.