The owner of a high-rise adjacent to The Cathedral of St. John the Divine is suing a Columbia senior for roaming the hallways with a “ninja sword” and allegedly beating his dog.

Police were called after Linhao Zhang was seen wandering the Morningside Heights building dragging a “ninja sword.”

Neighbors also saw him “continuously beat, hit, and drag his dog,” claims a Manhattan civil suit by Morningside Associates LLC, which seeks $500,000 in damages.

Zhang said that he had no idea he was being sued and that he “did not abuse my dog.”