If you had asked me this question last week, I may have answered manatee, platypus, or the harpy eagle.
But then I learned about the pangolin.
This is a very real animal called the pangolin, which is found in parts of Africa and Asia. Despite the reptilian scales, it’s a mammal. This photo makes it look much larger than it actually is, though the biggest pangolins can top the scales at around 70 lbs.
Have you met a pangolin? Which real animal seems the most like a fantasy creature to you?
Hummingbirds would be a convincing fantasy creature
Butterflies too (especially considering they transform from caterpillars
Jellyfish too, they’re pretty weird (especially Immortal Jellyfish https://en.wikipedia.org/wiki/Turritopsis_dohrnii)
There are quite a few insects that look like fantasy creatures (or that I wish were just fantasy creatures!)
Coconut crab. Pure nightmare fuel!
https://en.wikipedia.org/wiki/Coconut_crab