Dark Otter (ブラッコ burakko Bracco(?)) is an enemy that appears in the Stories of Legend, in first encountered in Claustronyctophobia in sub-chapter 21, Stairway to Darkness.
A black version of Otta-smack-u. A lot stronger (10x attack and 5x HP) than the normal Otter.
Dictionary
English Version
Bears his family's ultimate weapon: "Normal Rock", bane of clams everywhere. It's actually a plum pit, but don't mention it or he'll fly off the handle.