If you are a Labord's chameleon:
This little lizard spends around 8 months inside its egg. Once hatched, it spends four months maturing, eating, fighting for mates, and mating.
"It was just bizarre, because I could find only adults and no juveniles whatsoever," said study co-author Kristopher Karsten of Oklahoma State University.
"So I thought, Well, either my eye isn't trained very well to find these juveniles, or they're not there. And if they're not there, maybe that means that every one is the same age and they're an annual species."
After studying the chameleons for three more seasons, Karsten and his colleagues were certain that the entire population of Labord's chameleon (Furcifer labordi) turns over every year.
Then it dies. Unheard of among vertebrates, in that it spends more time incubating than it does living after its incubation.
Not a cryptoid, but still pretty strange.