Fairies, Unicorns, Dragons, Griffons, Centaurs, any animal or thing that has never been confirmed to exist but you believe does,
personally, I think Krakons exist, I think the sea is easily big enough for there to be something huge down there that we haven't spotted yet, and let's not forget that there are depths of the ocean that humans can never reach but creatures as big as blue whales venture to daily. Also I think that, by the power of statistics, no-one can logically deny the existance of aliens
so what about you?