Then in the year 1822 AD a doctor named Gideon Mantell found fossils of strange teeth that didn't match any known animal.

They resembled an iguana's, except tens of times bigger, so he named their owner "iguanodon" (iguana tooth).

They later found other parts of the skeleton—

but they'd been scattered underground, so Mantell drew up his hypothesis of what the whole body might've looked like, based on the remaining parts and the modern iguana.

However, more accurate reconstructions based on later fossils discovered ended up being totally different.

And so, this iguanodon standing before us now

is the "nonexistent fantasy animal created by human imagination" from Mantell's reconstruction!