What is fastest animal that ever existed?

The Largest Herbivore was the Wooly Mammoth and The largest Carnivore was The Giant short faced bear.

The Short Faced bear Was 2 Metres tall on all fours and three metres long but on its back legs was 4 Metres tall. It had a bite force of a ton.

The mammoth was 4 metres tall and 5 metres long.

Hope this helps