Crab Spirit

Crab Spirit(カニ灵,) is a spirit of a red king crab, that is Kouji Yamada's Guardian ghost.

About
Apparently he got along well with Damayaji, because he looked like a hermit crab. After Damayaji's death, both ascended to heaven together rather quickly.

Anime/Manga Difference
In the anime Yamada has a large teal green centipede-like spirit instead of the Crab Spirit