Demons

Gen 6:19: וּמִכָּל-הָחַי מִכָּל-בָּשָׂר שְׁנַיִם מִכֹּל, תָּבִיא אֶל-הַתֵּבָה--לְהַחֲיֹת אִתָּךְ: זָכָר וּנְקֵבָה, יִהְיוּ
And of every living thing of all flesh, two of every sort shalt thou bring into the ark, to keep them alive with thee; they shall be male and female.

On the spot Rashi says that shadim, or demons, were included, too. Why? Perhaps, because the verse says וּמִכָּל-הָחַי מִכָּל-בָּשָׂר suggesting that things that were alive, but not flesh, were brought on board as well. Rashi's source for this is Beraysis Raba, and I am quick to note that not all of BR found its way into Rashi's commentary. He includes only what can be used to address a perceived textual anomaly.