More specifically, dinosaurs.
I think it isn't hard to notice that in most fantasy worlds, you have your typical fantasy creatures (Gryphons, dragons, wyverns and wyrms. Trolls and unicorns, phoenixes, etc.), the typical animals we think of today (Goats, horses, wolves, bears, foxes), and creatures made up by the creator of the world itself. Occasionally, you may also find Ice Age animals such as mammoths and saber tooth cats, but anything predating those is practically non existent in the fantasy genre.
As a result, it's outlandish to think of something like a tyrannosaurus rex rampaging through a medieval country side (Despite how cool that actually sounds), and people don't even bother with it.
Personally, I'm a big fan of prehistoric life, which is evident in my username, so it's not uncommon for me to mix dinosaurs into fantasy settings. I find it entertaining, and while it sounds awkward at first, it can create for a much more diverse world.
There are other things I've put into fantasy worlds that most people probably don't, such as nuclear warfare and radioactive monsters (Yes, nuclear warfare and radioactive monsters). And believe it or not when you look at the reasoning behind it it makes a lot of sense. I'm not the type to just throw in some bull crap because 'Lol yes' and 'It sounds cool'.
So my question to the audience is this: What is your opinion on dinosaurs in a fantasy setting?