A shachihoko(鯱) is a Japanese sea monster.
Etymology
The above kanji can be pronounced in two different ways. When pronounced "shachihoko", it refers to the mystical animal mentioned above. When pronounced "shachi", it means grampus; a dolphin or orca. This is a source of confusion, even among the Japanese.
Appearance
Shachihoko has the head of a tiger and the body of a fish covered with poisonous spikes. On land it can transform itself into a full tiger. This imagery would be based on Makara in Hindu mythology. A representation of the Shachihoko was used in medieval Japan as a gargoyle.
Powers
It was believed that this animal could cause the rain to fall, and as such, temples and castles were often adorned with shibi (鴟尾) in this shape, in order to protect them from fire.