Conjure Stampede

You open a gate to the Feywild, releasing a horde of animal spirits from the target location. Animals that are size small or smaller will charge forward 60 ft in a 10 ft wide stampede until the end of your turn, running into anything in their path. All creatures in the path of the stampede must make a Strength saving throw or take 6d6 magical bludgeoning damage and get knocked prone. If a creature is a size smaller than the largest stampeding animals they are also pushed back the full length of the charge. On a successful save, the creature takes half damage and isn't moved by the stampede in any way.

Each animal spirit only has 1 hit point and will disappear early if it runs into an object of equal or greater size, if it's attacked, or if it takes damage from any other source continuous damage. The stampede contains an immeasurable number of animals, thus the effects of the spell will not be diminished if individual animals are killed before reaching the end of their charge.