Gigantism in animals always seemed creepy to me. The creepiest are the species I normally consider benevolent and non-threatening...birds, for example.
But really, I should know better. Giant birds were some of the most formidable predators on Earth after the extinction of the dinosaurs. They'd show us no mercy if they had a size advantage.
For some reason gigantic humans don't seem menacing at all. Maybe that's because I used to lech after tall girls when I was in High School.
Animals, on the other hand, are a different thing. When they're big it seems like a Biblical plague. It feels like a sign that something cosmic has gone awry, that the natural order of things is out of whack.
The only horses I know of that are still bred for height are Clydesdale's (above). Everybody wants to see how big they can get.
Of course, tiny creatures can be creepy too.
And, talking about tiny creatures, is that (above) really Shirley Temple?
