https://worldbuilderblog.me/2015/02/24/release-the-mounts/
Bison CR: 1/2 (100 XP)
Large beast, unaligned
Armor Class: 10
Hit Points: 30 (4d10 + 8) 4d10+8
Speed:
40 ft
Skills:
Trampling Charge. If the bison moves at least 20 feet straight toward a creature and then hits it with a hooves attack on the same turn, that target must succeed on a DC 14 Strength saving throw or be knocked prone. If the target is prone, the bison can make another attack with its hooves against it as a bonus action.
Senses: Passive perception 10
Languages: -
Challenge Rating: 1/2 (100 XP)
by theSong
Actions
Hooves. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) bludgeoning damage.
Ignores difficult terrain; Forrest