I heard that there is a Medrash that says that besides Noach, his wife, 3 sons, 3 daughters-in-law, animals, birds, and garbage there were others in the Teiva. What else was in the Teiva?
Just found a Yalkut Shimoni on Parshas Noach that mentions that Sheker wanted to come into the Teiva. Noach would not let him in as he had no pair. So Sheker cut a deal with Pichsa (tragedy) to join him in the Teiva. In exchange they made up that anything earned through Sheker would have a tragic end.