Otoshiana Maru was an oil tanker in New York Harbor where the gargoyles battled the Pack following the Pack's escape from Rikers Island. It was destroyed in the course of the battle. ("Leader of the Pack")
Otoshiana (おとし穴) is Japanese for "pitfall" or "trap." A fitting name since the Pack imprisoned Lexington, Brooklyn, and Bronx below deck and also laid a trap for the other gargoyles. Maru ((丸) is a suffix used in the naming of Japanese ships.