Crank (Blue)

One of the Maze's 4 fixed chests (each chest's colour is random). If it wasn't in the first, northern chest, check the others: one is along the passage down from the red room and over a railing toward the green-room side; another is up the step from the purple platform.

The blue trap: the blue room behind bars in the north-west, reached by climbing and jumping. The crushed Blob drops the Serpent Tail Shard.

Fandom pairs the blue trap with the Dual-Head Serpent Shard; two sources (Berserker's FAQ and game-kouryaku) say Serpent Tail Shard. It doesn't matter: any shard counts toward the goal.