Then with a crash came a great ringing shout: ra-hoom-rah! The trees quivered and bent as if a gust had struck them. There was another pause, and then a marching music began like solemn drums, and above the rolling beats and booms there welled voice singing high and strong.
We come, we come with roll of drum: ta-runda runda runda rom!
the Ents were coming: ever nearer and louder rose their song:
We come, we come with horn and drum: ta-runa runa runa rom!
Bregalad picked up the Hobbit and strode from his house.
Before long they saw the marching line approaching: the Ents were swinging along with great strides down the slopes towards them. Treebeard was at their head, and some fifty followers were behind him, two abreast, keeping step with their feet and beating time with their hands upon their flaks, As they drew near the flash and flicker of their eyes could be seen.
“Hoom, hom! Here we come with a boom, here we come at last!” called Treebeard when he caught sight of Bregalad and the hobbits. “Come, join the Moot! We are off. We are off to Isengard!”
“TO ISENGARD!” the Ents cried in many voices.
TreeBeard:Lord of the Rings