Would any of you encourage making up creatures of any sort? I have made up one and put it in my story, but I'm debating whether I should replace it with another creature that already exists.

Author-created animals are fairly common in fantasy, horror, and science fiction, but not in most other genres

If it's a story where it wouldn't be totally outrageous to have a made-up creature, I don't see why not. Most of my main characters are creatures that I've made up, though to be fair, they can look and act human when they want to.

Make up all the new creatures you want. The world of books needs new ideas. Or take one of the old one and change it some. Some creatures are just over used and need a new look to them. Take vampires, for example, one of the most used non human creatures there is. But also look at how people have changed them for their worlds that they write in. There are so many types of vampires. So I'm all for new things. Makes the book feel unique and not just another vampire or werewolf or elf story.

Thanks guys! Cause in my novel, I made up a creature called a darse, which is pretty much a reptilian horse-thing, but instead I'm gonna try using a gargoyle to replace it, and it's role is like a horse's, for humans to pretty much ride on it from place to place and used in battles and such.

oooh.. another gargoyle! :) My main character becomes a gargoyle. But people don't ride on him. It was a form of punishment.

It depends whether or not it fits correctly in your setting. If it's the modern-world where you simply just stuck in an animal or creature that has nothing to do with your plot or story, I'd recommend changing a few things. If it's a fantasy story, I think you'd be okay.

By the way, I love your idea! :)

Would any of you encourage making up creatures of any sort?

only if the story is sci-fi or fantasy...