"The Bloop" - are sea monsters a reality?

Does it have to be a huge animal? Maybe it is something small but loud. Cicadas are small and loud. Things might work differently underwater though.It could also come from a whale, but it would have to be a sound whales don't make often, since they have been studied so much. Maybe this is a sound made by an injured whale?Whatever made this sound, it definitely shows that there is still a lot for us to learn about the oceans.