Ape Mount

Proficiency when fighting with two handed improvised weapons, damage 1d10 (not when mounted)

Relentless endurance (see half-orc). When you are reduced to 0 hit points but not killed outright, you can drop to 1 hit point instead. You can't use this feature again until you finish a long rest.

Critical hit on 19 or 20

Armour: Adamantine Breastplate

Multiattack. The ape makes two fist attacks.

Fist. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 6 (1d8 + 3) bludgeoning damage.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 3) piercing damage.

Rock. Ranged Weapon Attack: +7 to hit, range 25/50 ft., one target. Hit: 6 (1d6 + 3) bludgeoning damage.

Trampling Charge. If the ape moves at least 20 feet straight toward a creature and then hits it with a fists 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 ape can make another attack with its fists against it as a bonus action.