Paul's Miracle Strategy Plan(1976)

Paul no Miracle Daisakusen

Paul is a young boy whose friend Nina is kidnapped by Belt Satan, the demonic ruler of another world. He daringly goes on a mission to rescue his friend. Pakkun, a plush doll with magic powers, aids him as they plunge into Belt Satan's dimension of living toys. Paul's journey is beset by many difficulties, but he also encounters a variety of delightful wonders.

(Source: Anime News Network)