Before the advent of military tanks as fighting machines during WW1, decisive battles have been won from the tops of elephant tanks to strike terror and crush the enemies.
Elephants being herbivorous are sustainable tanks during wars in Asia especially where they ubiquitous. During the Portuguese conquest of the Melaka kingdom in 1511, it is recorded in the Malay Annals (Sejarah Melayu) that Malay warriors rode on elephants into the midst of battle. My guess is that the thunderous sound of big canons from the ships would drive the elephants (and the Malay warriors) on stampede away from the battlefront!
This work by an anonymous Dutch painter shows the power of an elephant on the battlefield, with a large tower built on its back.
On an elephant to strike terror on the enemies.
Medieval Latin manuscript from around 1500 depicts an elephant trampling a man. Note the impressive tower on the elephant's back.
Alexander the Great first discovered the use of elephants in war at the Battle of Gaugamela. Despite his fear of the beasts, fate was on his side during the battle.
Hannibal's elephants on huge rafts crossing the River Rhone.
Elephants in Cochin, on the warpath.
The Delhi Field Force of the East India Company advancing towards the Mughal capital. The Mughal defeated, the colonialists took over to rule India.