Mattel Barbie Totally Yo-Yo Nikki that came out in 1998. The up and down motion of the tiny yo-yo in Nikki's right hand was made by pushing a lever up and down on the doll's back. Also came with an extra outfit and other accessories.
This yo-yo-based product line, which included three different dolls from Mattel, was one of the very few yo-yo items that came out during the yo-yo boom of the late 20th century marketed specifically to younger girls.
The back of the box is identical across all three dolls; only the printed doll name is different.
