Pulsar  

パルサー(PULSAR)

The animated series you're referring to is called "Ebiten" and it aired in 1991 on Japanese TV program Miyake Yuuji no Ebizori Kyoshou Tengoku. It showcased works of independent film makers, featuring clay (technically gypsum) characters set to music with robots, sci-fi motifs, and alligators with human arms. The series introduced the prototype character Pulta, which was later used in Bowda Katsuhis Robot Pulta anime by NHK.