It's undoubtedly animal cruelty, but I can't think of anything much more intimidating on the battlefield pre-industrialization. You can see why Hannibal used them against the Romans. They must have been shitting themselves in terror seeing those giant creatures charging at them.
As terrifying and formidable as this looks, I was reading that one of the often overlooked aspects of war elephants is their logistic and engineering value. Imagine if your army had bulldozers and forklifts while your enemy had shovels and ropes.
The apparently were really good at destroying formations, especially if the managed to make their way behind the front. Also they are highly trainable.