Takoyaki, or fried octopus balls, are a beloved Japanese snack — so it’s not all that surprising that there are multiple gadgets to help the average cook satisfy their craving at home.

OSAKA—An electric guitar with a “takoyaki” (octopus dumpling) cooker for a body was unveiled here to promote the Osaka delicacy. The presentation was held on Aug. 8, known as the “Day of ...