Tuki is the "sneaky, snakey seller of magical secrets" in Shantae: Half-Genie Hero. She appears at various points throughout the game to offer the player new dances in exchange for old ones, as well as selling exclusive dances, such as the Warp Dance, Dryad Dance, Revive Dance, and Obliterate Dance.
In order to shop with Tuki, the player must find her purple pot in the game's levels. Upon "ringing" the pot by hitting it, Tuki will appear.
She is quite similar to the Freebots and Quick Draw from Skylanders: Giants, being based off an enemy but being friendly rather than attacking. The Freebots and Quick Draw, however, play a game known as Sky Stones, while Tuki just runs a shop.
That said, she's not the series' first 'friendly enemy' - that honor belongs to the Tinkerbat who fixes Shantae's roof at the end of Shantae .
While most of Tuki's wares are exclusive, the Warp Dance is not, and can be bought in the Scuttle Town Item Shop. It's the same price regardless of who Shantae buys it from.